Antislip flexible materials and methods for their making and use

ABSTRACT

A method for forming an antislip material. A flexible thermoplastic carrier is provided. A hot release surface is provided. Provided is a first layer of discrete thermoplastic particles, sifting on the hot release surface. The discrete particles are above their softening temperatures, providing in the first layer a tackiness. The method includes contacting the carrier with the tacky first layer for sticking the first layer to the carrier, and thereafter removing the carrier, and therewith the tacky first layer stuck to the carrier, from the release surface. Thereby the carrier is provided with a hot, preferably discontinuous and/or elastomeric antislip coating. With a heat energy of the hot coating a bond is formed between the carrier and the coating. The removing of the carrier includes pulling the carrier out of the contact with a pulling-out force. The temperature of the hot release surface is above the melting temperature of the carrier. The carrier would be spoiled, if heated completely to the temperature of the release surface and simultaneously pulled with the pulling-out force. Therefore the contacting time is kept shorter than a minimum time required by a heat of the hot release surface for spoiling the carrier. Flat-topped roughening projections can be included in the antislip coating.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 16/304,587, which is a 371 of international applicationPCT/HU2017/000029, which claims the priority benefit of Hungarianapplication P1600341, the entire disclosures of which are incorporatedherein by reference.

FIELD

On the one hand, a first aspect of the invention relates to methods forusing discrete thermoplastic particles heated to a tacky state formaking an antislip, preferably roughened coating layer on a surface of athermoplastic flexible carrier suitable for use, for example, as anantislip flexible packaging material. On the other hand, further aspectsof the invention relate to antislip flexible packaging bags or wraps,with an outer surface having roughening projections, and methods fortheir manufacture and use.

BACKGROUND

Advantages of flexible thermoplastic packaging materials, such as filmsand woven or nonwoven fabrics, include that bags and wraps madetherefrom can be recyclable, they (both films and fabrics) can beheat-shrinkable onto contents for a tight package, they can be formed orfixed or closed with clean and fast heat-binding or fusing or weldingetc. They, however, can be too slippery. That can cause stacks of baggedor wrapped goods to lose their shapes, even to fall apart, in transport.That can also cause, for example, a worker walking atop a block oftimber, wrapped in plastic timber wrap, to slip and fall especially ifthere is moisture, snow or ice on it. Non-thermoplastic, for example,kraft paper bags can also be too slippery for some purposes, especiallywith fine dust contamination. There are possibilities to decrease aslipperiness of a surface of a flexible material. One can provide anon-slippery (for example, elastomeric) substance in the surfaceproviding a high-enough coefficient of friction even if the surface issmooth. Such solutions can provide high values both in static andkinetic coefficient of friction. Such solutions can work well, but theycan be sensitive to such contaminants as a surficial presence of finedust, moisture, ice or grease, or, for example, a slip agent migratingto the outer surface of the antislip layer from the packed-up contents.It is, however, also possible to provide, for example in a bag, aroughened outer surface whose antislip protrusions create at least someantislip mechanical interlock with suitable features of a surface ofanother bag. That can work even if the substance thereof is notnon-slippery (e.g., elastomeric) in itself. We note that rougheningprojections smaller than about 10 or at most 15 micrometres are usuallyused for antiblocking purposes, and it is roughening projections largerthan about 10 or 15 micrometres that are usually used for antislippurposes. Such solutions can typically provide good staticcoefficient-of-friction values, and perhaps not so good kinetic ones.Further, it is possible to exploit both effects simultaneously, byapplying a non-slippery (e.g., elastomeric) substance in the antislipprotrusions themselves. Antislip flexible materials can also be used innon-packaging fields, for example as roof underlayments, geomembranes,sanitary covering materials for the building industry, or sanitaryunderpads in human health care or in veterinary medicine. Further, it ispossible to include the providing of the antislip feature in the makingof the web itself such that when the film or fabric is first born it isalready antislip. For example, an elastomeric component can be used inthe extrusion, or a roughening additive can be blended into thepolymer-to-extrude. That integrated manufacturing approach hasdrawbacks. For example, it can be very difficult to simultaneouslyoptimise the antislip parameters and optimise the manufacturingparameters of the film or fabric itself. On the other hand, it ispossible to provide a ready-made web, for example of film or fabric, andmake it antislip in a subsequent, independent operation. That typicallyincludes either an embossing of the web or forming an antislip (e.g.,elastomeric and/or rough) coating layer on the web. That independentmanufacturing approach has advantages. It makes it possible to optimisethe antislip parameters of the product independently from themanufacturing parameters of the web itself. In addition, it makes itpossible to first optimally source, and store, a larger supply of acommodity web and then convert antislip products from it customised, andwith a fast response, to individual customer requests.

In any case in general, it can be considered to be a drawback if theantislip flexible (e.g. packaging) material does not provide any one ormore of a suitable apparent (static and/or kinetic) coefficient offriction, a suitable flexibility, a suitable isotropy of the friction, asuitable isotropy of the flexibility, a suitable wear resistance of theantislip surface and a suitable contamination-resistance of the antislipfeature. In case a packaging material can be used to heat-shrink aroundthe contents of the package then it is considered to be a drawback ifits heat-shrinking behaviour is compromised by its antislip features,for example, if the packaging material loses (when it is made antislip)some or all of its homogeneity, or isotropy, of shrinking. A heatshrinkability of the antislip roughening projections in themselves canbe a drawback, because they could deform the packaging material becauseof their undesired shrinking from the heat, for example when theflexible material is fused, for example, a bag or wrap is formed from itand/or closed by fusing or welding, or when the packaging material isheat-shrunk to the contents of the package or when a bag of antislipheat-resistant (for example paper) material with heat-shrinkableantislip roughening projections gets filled with hot contents likecement, or when a load of packages packed in antislip bags is coveredwith a shrink hood that is heat-shrunk onto the load. It is a drawbackif the antislip roughening projections lose their shapes too easily(either due to their mentioned inherent heat shrinking, and/or due totheir becoming too liquefied and thus too much exposed to an effect ofsurface energies and beading out) in response to a heat during thementioned fusing, shrinking or hot filling. It is also a drawback ifduring a (manual or other) slitting, or cutting (for example, cutting tosize or shape), of the flexible (e.g. packaging) material one has toface an essentially inhomogeneous or anisotropic resistance of the (e.g.film or fabric) material to the slitting or cutting, possibly caused bythe antislip features. Another drawback can be a lack of economy, forexample due to a use of antislip components in surface areas where theyare not exploited, or due to heating up such parts of a web as would nothave to be heated up for the particular purpose, or due to a use of anunnecessarily thick or heavy antislip layer or due to a use of a tooexpensive machine, process step, and/or material component. Anysolutions based on features hindering recycling (for example, usingrough mineral particles for an antislip roughening) are disadvantageous.Methods, for making antislip flexible materials, that inherently hindera use of cheap recycled materials as raw material are considereddisadvantageous. Such hindering can be caused, for example, by the factthat recycled materials can have parameters of a wider and moreuncertain range than virgin ones or can have a shorter time ofresistance against oxidation or degradation, and can also contain tracesof contaminants (such as ink residues or fine dust) possibly making themunsuitable for more sophisticated devices or process steps.

Examples for the “integrated manufacturing approach” follow. In U.S.Pat. No. 7,314,662 solid particles are mixed, in the extruder, into thefilm's melted substance to form protrusions in the surface of the film.As a drawback of such solutions, the embedded particles break theuniformity and even the continuity of the film layer in which they areembedded, possibly weakening it. Also, only a part of each particleprotrudes from the film. A desirable undercut of the antislipprotrusions is usually impossible to provide and they are relativelyblunt-shaped. Further, the size of the protrusions, as well as thenumber of protrusions per surface area, is very limited. Further, thewhole perimeter of the film tube must be roughened. Further, the methodcan not be used for roughening non-thermoplastic webs. U.S. Pat. No.6,444,080 and HU 0202948A2 and U.S. Pat. No. 7,765,774 together describethat solid thermoplastic powder particles are blown onto the hot, tackysurface of a blown film bubble under its freezing line. The particlesstick to the tacky film surface. A heat energy of the hot, molten filmis used for fusing the stuck particles to the film. It has the advantagethat the particles do not necessarily weaken the wall because they donot have to enter the wall. The protrusions can have sharply protrudingshapes, with undercuts, providing a shearing interlock with similarprotrusions of another film. They can even provide an effective antislipmechanical interlock with a fibrous engaging material, such as anordinary nonwoven. In addition, unlike hook and loop fasteners, thenonwoven can be lifted off, vertically, from the rough surface withoutdifficulty, i.e., the engaging system can have essentially zero liftingor peel-strength. The solution also has disadvantages. The blowing-on,or sprinkling, of the particles makes it difficult to control the actualconfiguration of the particles along the film surface. The particles cannot be pressed onto the hot bubble surface for a strongerfixing-by-fusing, therefore the roughening protrusions can have verysmall footprints and can tend to break off too easily. For the samereason, they can be prone to leaning to the side, around their foot, inresponse to a shearing load thus losing their interlocking capacity. Theprotrusions are of non-uniform heights, having randomly pointed topswhich can make the product feel rough to the touch and difficult towrite on with a pen or stick on a label or tape, and a printing of theroughened surface may also not be beautiful enough. The protrusions, ina side view, look like powder particles having a shape generally similarto a sphere that looks as though somewhat embedded into the basesurface. They are of various heights. An example protrusion shape isillustrated in FIGS. 1c and 1d of HU 0202948A2 (side elevations of asingle protrusion, from two perpendicular directions): as can be seen,the shape of the protrusion is somewhat irregular, and we note that itstop is not flat which can be seen from its FIG. 1d. Another exampleprotrusion shape is illustrated in FIG. 3. of U.S. Pat. No. 7,765,774(side elevation of an antislip protrusion). To engage with a fibrousengaging material, each protrusion should enter deeply into the nonwovenso that their widest (as meant in their side view) part can catch somefibres. It means that it is not enough if the top of the protrusionreaches the fibrous engaging material. Due to the mentionedembedded-sphere-like shape, their widest (as meant in side view) part isusually somewhat closer to the base surface than to the top of theprotrusion, therefore it is too close to the base surface and it is notclose enough to the top of the roughening protrusion. In addition,taller protrusions prevent shorter ones from penetrating the fibrousengaging material by keeping the fibrous engaging material (or thefacing film, to which the fibrous engaging material is adhered) awayfrom the smaller protrusions, acting like spacers. That can lead to onlyfew of the protrusions becoming active with the fibrous engagingelement. Similarly, to interlock with each other the abutting opposingrough films should abut on each other perfectly otherwise the widest (asmeant in side view) parts of each protrusion can not catch each other,and the tallest protrusions act like undesired spacers. The product canbe sensitive to protrusions getting impressed, forming depressions underthem in the film surface, because that further decreases the freeheights of their undercuts, i.e., the distances between their widest (asmeant in side view) parts and the base surface. The free height canfurther be decreased in an undesired way by a buildup of fine dust orsnow. Though protrusions of such shape provide an antislip interlockwith an opposing identical rough bag surface, interestingly, they canappear to increase the slip over a smooth surface, for example a smoothbag surface. We believe that it is the result of the total abuttingsurface of the product being extremely small, namely it is constitutedby the small top areas of the (few tallest) protrusions. Further, it isnot easy to make a film tube that is only roughened on one side, due toits asymmetry in the film blowing. Further, the blown, tacky film caninherently not be printed before the roughening. The U.S. Pat. No.6,444,080 document mentions the possibility of re-melting a pre-madefilm for using it instead of the melted film in the blown-film-bubble,but that would be very difficult to achieve without warping and spoilingthe film and it would also be uneconomical to reheat the film. Also, thesolution can not be used for roughening a packaging fabric or anon-thermoplastic web.

Examples for antislip packaging materials according to the “independentmanufacturing approach” are as follows. In DE 3437414 A1 embossing pinsare used to raise individual points of the film, in U.S. Pat. No.3,283,992 linear ribs are raised from the original surface and U.S. Pat.No. 2,917,223 describes an antislip bag with mating embossments.Drawbacks thereof include that a desirable sharp character, preferablyeven with undercuts, of the roughening protrusions can not readily beprovided, especially in case of embossing woven fabrics, further, thesubstance of the antislip protrusions is inherently identical with thatof the wall, and the hollow, not solid, embossed protrusions are notstrong enough (for example, can be compressed flat), and the wall can beweakened. Further, with antislip protrusions of rib-like, elongatedshape (as seen in a top view thereof) generally a desirable isotropy(i.e., providing uniform antislip engagement in all shearing directions)of the antislip surfaces may not be provided and also a flexibility ofthe packaging material can be compromised. Further, with matingembossments the antislip effect may only work in few particularorientations, not being isotropic at all.

DE 19938828 (A1) describes a method for providing a plastic film withnon-slip finish. A pattern of a high-coefficient-of-friction material isdeposited onto the film. For example, a hot melt adhesive is melted upand dripped from the air onto the film. A drawback of the solutionappears to be that it is difficult to simultaneously control theconfiguration of the drops along the surface and the temperature of thehot melt at the moment it contacts the film. It is particularlydifficult to provide an efficient and economical monolayer of the dropson the film. Further, not any compressing of the melt with the film,during the bonding, is mentioned. Further, hot melt adhesives as well asapplicators suitable for such application are expensive and in theirrespect a use of recycled materials, in the melt, is not favoured.Further, such hotmelt adhesives as are suitable for the mentionedpurpose, if left exposed and especially if facing with another similarsurface, can tend to block if the bags are stored in a warm storehouse.It is especially a problem if such a blocking of the empty, yet-unfilledbags arises. The method is dedicated to decreasing the slip on a basisof a high-coefficient-of-friction substance and it is not suitable to beset to alternatively be used for making an antislip coating based, orpartly based, on a mechanical interlock of a roughened surface.

SUMMARY

There is still a need for methods and antislip flexible materialproducts alleviating one or more of the mentioned drawbacks of thebackground art. In regard of our method inventions and methodembodiments, for forming antislip flexible materials, and further inregard of our product inventions for antislip packaging bag or wrapproducts, our objectives further include one or more of the following:

-   -   providing new methods for making a flexible material antislip        with the independent manufacturing approach, which provides        independence from a manufacturing of the flexible material        itself;    -   methods useful for converting films, fabrics and flexible        composites even if they are heat-sensitive;    -   methods suitable for flexibly setting a ratio of a friction        based on a surficial substance and a friction based on a        mechanical interlock of roughening projections, possibly also        influencing the kinetic and static friction;    -   methods without an inherent need for expensive equipment and raw        materials like those usually used for example with hot melt        printing or melt extrusion;    -   methods in which it is possible that the material of the        antislip coating can be kept molten for a very short time only,        to prevent oxidation or degrading even with cheap raw materials;    -   methods in which even recycled raw materials might be favourably        used in the antislip coating;    -   methods capable of high line-speeds, for example above 50 m/min,        for example about 80 or 160 or even more m/min;    -   methods flexible in speed, possibly adaptable for stand-alone as        well as in-line operation with various existing manufacturing        and converting technologies of various speeds;    -   methods producing antislip materials with an apparent friction        easily and flexibly settable between wide limits for example        through setting the closeness and/or shape of their antislip        protrusions;    -   methods that can add material to a carrier material with        heat-bonding (preferably with fusing or welding), which can be        fast and clean and compatible with recycling;    -   methods that can maximise and/or more precisely control the        added heat useful for the heat bonding, for example through        maximising and/or precisely controlling the temperature of an        added hot material at the moment it is actually added;    -   methods that can add great, but only local, charges of heat        energy, for the heat bonding, without an overall melting or        spoiling of the carrier, resulting in stronger and        blocking-resistant heat-bonds, preferably even without an        inherent need for a forced cooling of the carrier;    -   methods that can form a strong bond between an added material        and a carrier material due to using a combination of        heat-bonding (preferably fusing or welding) and a mechanical        compression between the added material and the carrier material;    -   methods that can add antislip features both to porous and        non-porous flexible materials,    -   methods that can add antislip features to a flexible material        without essentially compromising its strength, flexibility, heat        shrinkability, isotropy of flexibility, and/or isotropy of heat        shrinking behaviour,    -   methods that can provide antislip features without penetrating        and/or weakening the flexible carrier and simultaneously working        with only a possibly small amount of added material, with an        efficient exploitation of the added material for the antislip        purpose;    -   manufacturing methods better suiting the need for a beautiful        printing of the antislip products, and such products;    -   methods, for making antislip products with antislip protrusions,        including a possibility to set or fine-tune a shape of the        protrusions,    -   (methods for making) antislip products with antislip protrusions        that may not have an essential inherent heat shrinkability in        themselves,    -   (methods for making) antislip products with antislip protrusions        that can at least partly survive a heating or heat-shrinking of        the antislip product, due to a relatively low melt index of the        antislip protrusions,    -   (methods for making) antislip products with antislip protrusions        that work well in a mechanical interlock due to the antislip        protrusions having a shape of an undercut and/or sharply        protruding character;    -   (methods for making) antislip products with antislip protrusions        that can work well in a mechanical interlock simultaneously also        providing an acceptable or improved friction on smooth surfaces        for example through excluding small-tipped or pointed shapes in        the antislip protrusions;    -   (methods for making) antislip products with        contamination-resistant antislip protrusions that can        effectively catch a counterpart fibrous material or roughened        material without a need for a deep penetration of the        protrusions into the counterpart fibrous material or roughened        material;    -   (methods for making) antislip products with antislip protrusions        that can effectively catch a counterpart fibrous material        without causing difficulties in lifting or peeling the        counterpart fibrous material from the antislip product (for        example with a relatively wider foot of the antislip        protrusions);    -   (methods for making) antislip products having a low and/or        isotropic slitting- or cutting-resistance;    -   (methods for making) antislip products with a possibility of        antislip roughening projections that are more wear resistant        (for example with a relatively wider foot);    -   (methods for making) antislip products roughened with antislip        roughening projections that can be easier to write on, or stick        on a label or tape, and can feel smoother to the touch;    -   (methods for making) antislip products roughened with antislip        roughening projections that can be universal in their interlock        for example due to a real random size and/or distribution of the        projections;    -   (methods for making) antislip products more resistant to        blocking in a warm storehouse;    -   improved economy;    -   combinations combining a plurality of the mentioned        objective-aspects for possible synergistic effects;    -   methods for use of the mentioned products;

Our recognition includes a combination of several aspects, as follows.If we want to add and heat-bond a hot polymer layer to a cold film orfabric carrier, a heat energy of the added layer must be high enough forforming a heat bond. Namely, if the cold carrier does not become hotenough at least where the bond is to be formed, the bond can remain tooweak, even if the bond is purely based on a hot-melt adhesion of theadded layer (which, however, is not even necessarily the best solutionfor our objectives). The thinner the added layer, the lesser heat it canbring, for successfully heating up the cold film or fabric. If, inaccordance with the needs of an economical and flexible antislipcoating, we select a low average surface weight of the added coating, wecan still reliably maintain the necessary heat energy by maintaining aconsiderably high and precisely controlled temperature thereof. If wewant to avoid a later blocking of the product (for example in a warmstorehouse), and therefore want to use high-melting-point polymers inthe added layer, the necessary temperature of the coating layer is evengreater, which is especially true if we want to expressly weld thecoating layer to the carrier instead of applying a pure hot-meltadhesion. But even if the bond is not (purely) a weld, a suitably strongand non-blocking bond can need such high temperatures of the bondedparts as melts both of the bonded parts at the place of the bonding. Theneed for an expressly high temperature in the coating is furtherincreased if we want avoid applying a very strong or robust compressionbetween the (e.g. film or fabric) carrier and the hot coating, eitherfor preventing the coating from penetrating the fabric and/or forpreventing discrete melt particles in the coating from being pressed toothin and flat. Very thin continuous coating layers can usually bedifficult to bond to a carrier at a high temperature because they canlose their heat energy with cooling before a heat bond is finished. If,however, we provide the hot coating in a form of discrete hot particlesinstead of a very thin continuous layer of the same apparent surfaceweight then the heat can be more efficiently exploited for the localheat-bonds of the particles, even if the particles are finallycompressed to form a flat surface, because the particles have a localthickness greater than the average “thickness” (calculated from surfacemass) of the coating layer, therefore they can carry a greater localheat energy charge, because they have a higher volume-to-surface ratiothan a thin film (the volume storing the heat energy while the surfacedissipating it). In addition, a low-surface-mass layer of discreteparticles is easy to form (for example with powder scattering) without amolecular orientation in it while a continuous thin film layer, of thesame low surface mass, is really difficult to make without a molecularorientation in it, which is important, for example, in the regard of anintact or isotropic heat-shrinkability of the product. The discretelayer can be formed with cheaper machinery and from cheaper (possiblyeven recycled) materials than a thin continuous layer. Forming adiscrete layer can handle higher viscosities in the melt than forming athin continuous layer. In our case the hot discrete particles cantypically be of a significantly (for example, orders-of-magnitude)higher viscosity than usual inks or other liquid hot-melt polymercompositions used in ordinary printing operations. In addition, forexample powder scattering can be used with much higher line speeds thenhot-melt printing. Therefore in our case one can freely choose,substantially just by selecting a compression value, to either form acontinuous (for example elastomeric) final layer or a discontinuouslayer, for example a layer of discrete roughening projections, from alayer of the hot discrete particles provided. If we provide the molten,tacky particles distributed, and sitting, on a hot release surface thenwe can simultaneously provide a suitably controlled distribution of thematerial along the surface and a suitably high and controlledtemperature thereof up to the moment of their transferring to thecarrier (the particles are essentially not allowed to cool before theyare transferred to the film or fabric). Namely, if we contact thecarrier with the hot particle layer that is sitting on the hot releasesurface, a very short contacting time can be enough for transferring thehot particles from the release surface to the carrier. If we exploitthat fact, and select a sufficiently short contacting time beforeremoving the heat sensitive (and freshly coated) (e.g. film or fabric)carrier from the hot release surface than the hot release surface,though exposed between the hot particles sitting on it, does not haveenough time to heat the carrier to an undesired extent, even if therelease surface is so hot as would readily melt the carrier if givenenough time. This way the amount of heat transferred to the freshlycoated carrier can be, nearly or virtually even perfectly, restricted tothe useful amount of heat carried within the hot coat and the carriercan be protected from the potentially harmful heat transferred (e.g.radiated and/or conducted and/or convected) from the hot release surfaceitself. Rotating-winding technologies readily provide the possibility ofvery short nip contacts and the possibility of easily finding thesuitable contacting time by trying different line speeds. At the end ofthe contact and before the separation, the molten particlessimultaneously contacting the cold carrier and the hot release surfacewill have adhesion levels with both the carrier and the release surface.As we found, the hotter the release surface, the weaker the adhesionbetween the release surface and the particles. (To illustrate this: ifsoftened polyethylene particles are held between, and in symmetricalcontact with both of, two release surfaces, one of them being colderthan the other, but both release surfaces of temperatures above asoftening temperature of the particles, then when they are separated,the particles will stay with the colder release surface and get releasedfrom the hotter one.) It means that the hotter the release surface atthe separation, the easier it is to separate the molten particles fromthe release surface, which also leads to preferring an expressly hotrelease surface. On the other hand, as we found, the colder the frontsurface of the carrier, the stronger the adhesion between the frontsurface and the tacky particles during the contacting. It means that thecolder the front surface at the separation, the easier it is to preventthe molten or softened particles, touching the front surface, from beingdetached from the front surface, which leads to preferring an expresslyshort contacting time, in order of preventing the front surface fromessentially getting heated up before the end of the contacting time. Achoice of the substance of the hot particles as well as of their sizeand closeness in combination with a choice of an extent of theircompression provide the method with a great flexibility. A suitablesimultaneous selection of the surface weight and temperature of the hotparticle layer and of the carrier, the method can be free of a need forany pre-heating of the carrier or any forced cooling, and such suitableselections seem to be very practicable with flexible films and fabricsordinarily used for example as packaging materials. Further, werecognised that such forming of antislip roughening projections on thecarrier can be used for providing projections of uniform height, eachprojection having its widest (i.e., widest in side view,) part close toor at its flat top, whose benefits include that such a projection cancatch a fibre of a fibrous engaging material as soon as the two get intoa contact, there is not any need for the projection to deeply penetratethe fibrous material. Analogously, two such mentioned rough surfacesalso interlock with each other much better. This leads to virtually allof the roughening projections uniformly taking part in the shearinginterlock, greatly increasing the efficiency and shear strength of theinterlock, without generating any difficulties at lifting off theinterlocking parts. This kind of configuration, as we found, can havefurther benefits, as will become apparent later herein. Some furtherparts of our objectives and recognition will be described later herein.

In a first aspect, the essence of a method invention is a method forforming an antislip flexible material, comprising:

-   -   providing a flexible carrier having a front surface,    -   the provided carrier at least partly including a thermoplastic        first polymer,    -   the carrier having at the providing a temperature sufficiently        low to keep the first polymer from melting or softening,    -   providing a hot release surface of a first temperature,    -   providing a first layer of discrete particles including a        thermoplastic second polymer, sitting on the hot release surface        and projecting from the hot release surface to corresponding        terminal ends,    -   in the provided first layer the discrete particles being at        least partly of or above a second temperature, the second        temperature being above a softening temperature of the second        polymer, providing in the first layer a tackiness of at least        the particle terminal ends,    -   bringing into an, at least partial, contact, and keeping in the        contact for a contacting time, the front surface of the provided        carrier with the tacky first layer sitting on the hot release        surface for at least partly sticking the first layer to the        front surface, and thereafter    -   removing the carrier, and therewith at least partly the tacky        first layer stuck to its front surface, from the release surface        thereby providing the carrier with a coating of a hot state, and    -   utilising a heat energy of the hot coating forming a bond        between the carrier and the coating,    -   thereby providing an antislip coated flexible material including        the carrier and the coating bonded thereto;    -   the removing of the carrier including pulling the carrier out of        the contact with a pulling-out force,

the method further comprising

-   -   providing the first temperature above the softening temperature        of the second polymer, and    -   providing the first temperature above any one or both of a        melting temperature and a softening temperature of the first        polymer;    -   selecting, for the providing, a carrier that is spoiled (for        example through one or more of breaking, stretching, shrinking,        and warping) if heated completely to the first temperature and        simultaneously exposed to the pulling-out force; and    -   selecting the contacting time shorter than a minimum time, which        minimum time is determined such that the spoiling of the carrier        by exertion of heat by the hot release surface is limited to a        predefined allowable extent.    -   The product which is made directly by the method, i.e., the        antislip coated flexible material, can be, for example an        antislip packaging material, for example one or more antislip        packaging bags or packaging wraps or an antislip packaging        material on the reel, or other, for example, non-packaging        antislip coated flexible material. The flexible carrier can be        any suitable carrier, for example a film, a coated and/or        uncoated woven and/or nonwoven fabric and/or any compositions,        laminates etc. thereof. The carrier can be of a multiwall        structure or it can be of a single wall. The carrier can be, for        example, a single wound sheet material, or it can be a tube, or        a gusseted tube, or a centre folded web or any other suitable        configuration. The tube can be an originally formed tube (for        example, a blown film tube or a circularly woven tube) or a tube        formed, from a sheet web, for example with a lengthwise sewing        or welding or adhering of web edges. Further, the carrier can be        an endless carrier, typically stored on reels and processed with        unwinding and rewinding, or, the carrier can consist of        individual units, for example, individual bags or sheets of        material. The first polymer, as well as the second polymer, is        thermoplastic and can respectively include one or more        homopolymers and/or copolymers, for example a blend thereof etc.        The first polymer, as well as the second polymer, may further        comprise, for example, pigments, light absorbers, light        stabilizers, antioxidants, fillers, plasticizers, rheological        additives, or mixtures thereof etc. The whole carrier can be of        the first polymer or at least one or more parts of the carrier        contain the first polymer. The front surface can include first        polymer or can be free of first polymer. The carrier can, in        general, further contain non-thermoplastic components, that can        be, for example, structural layers and/or surficial coatings,        for example ink-print layers. When the carrier is provided, it        is cold enough to keep its first polymer from melting or        softening. For example the carrier of room temperature is        provided, i.e., a pre-heating of the carrier is in general not        necessary, though possible. The release surface can be        constituted by a surface of a sheet, or belt, or drum, or roll,        or any suitable structure. Its shape (for example flat belt),        surface morphology (for example smooth) and chemical composition        (for example fluorocarbon) are preferably formed to facilitate a        release of a hot, tacky polymer. If the release surface is on an        outer side of an endless (for example glass fabric) belt then        the inner side of the belt should preferably also be provided        with a release surface for its better sliding on plates,        preferably heating plates. The heating plates can be planar or        preferably slightly convex for a positive belt-contact. With        respect to great line speeds achievable with the method, it is        preferable to avoid a complete exclusion of air in the contact        between the inner surface of the belt and the (heating) plates        that it slides on, to avoid a blocking of the belt. This        avoiding can be done, for example, with an inclusion of some        texture in the contact or with providing a thin air pillow in        the contact etc. The release surface is hot, which can be        provided, for example, by heating the mentioned sheet or belt        etc. from its underside and/or heating the release surface with        an (infra-red) lamp-light irradiation of the release surface        and/or with an electromagnetic heating and/or providing hot gas        and/or hot (heat-radiating) surfaces around the release surface        etc. The provided first layer is discontinuous and contains the        discrete particles including the thermoplastic second polymer.        The particles can, in general, be foamed or hollow, however        solid particles are usually more preferable. The particles can        totally consist of the second polymer or they can further        include other constituents, too. The particles can have the form        of, for example, powder granules, droplets, chips, micropellets,        fibre-sections and/or any other suitable particle shapes. A        particle, sitting on the release surface, can include, for        example, one (e.g. more or less melted) powder granule, but it        is also possible that a particle, sitting on the release        surface, includes a plurality of such, joined, powder granules,        “joined” meaning that adjacent powder granules no longer have a        distinct boundary layer when viewed under magnification. For        example, there can be discrete particles each consisting of two        or three joined powder granules, respectively. The terminal end        is the top end, farthest from a foot, of a particle with respect        to the release surface on which the particle is sitting. The        discrete particles are at least partly of or above the second        temperature, which means that some or all particles have one or        more parts, or their entireties at or above the second        temperature. The second temperature being above the softening        temperature of the second polymer makes the second polymer        tacky. A tackiness is provided in the first layer, and        particularly at least in the terminal ends of the mentioned some        or all particles. In a practicable case, for example, all        particles are hot and tacky in their entireties. A tackiness of        the particles can help maintain a suitable distribution of the        particles along the release surface by fixing them there against        slipping or rolling about. The front surface is brought into an        at least partial contact with the tacky first layer while the        tacky first layer is sitting on the hot release surface. The        contact being at least partial means that at least one or more        parts (or the whole) of the front surface are brought into the        contact with at least one or more parts (or the whole) of the        tacky first layer. For example, some of the discrete particles        take part in the contact while others (for example the smallest        ones) do not. The establishing of the contact typically involves        the front surface exerting a positive force on the tacky first        layer. The configuration, of the discrete particles sitting on        the hot release surface and projecting from the hot release        surface to corresponding terminal ends, inherently helps the        front surface to form a solid contact with the discrete        particles while simultaneously staying away from, or at least        avoiding a strong contact with, the hot release surface exposed        between the discrete particles. (For example this feature        distinguishes the current solution from known solutions in which        molten particles, provided for contacting, sit completely within        indentations of hot gravure-roll or similar surfaces.) During a        short time interval of the mutual contact, the contacting time,        the tacky first layer (or, as we said, one or more parts        thereof) can form an adhesion with the front surface and can        start to transfer heat into the front surface while, on the        other hand, the hot release surface can still provide a hot        backup contact against a cooling-off of the first layer even        though only for a very short period of time. As a result, the        first layer at least partly sticks to the front surface, which        means that there can also be one or more such places where the        first layer does not stick to the front surface, however, in        practice, the whole contacting surface of the first layer should        preferably be made to stick to the front surface, which can be        facilitated, for example, with a suitable, for example moderate,        compression therebetween. When the carrier is removed from the        hot release surface, therewith at least partly the tacky first        layer, stuck to its front surface, is also removed from the        release surface, which means that one or more parts of the tacky        first layer can remain on the release surface even at such        places where the first layer stuck to the front surface. At such        places, for example, the whole thickness or only a part of the        thickness of the first layer can stay on the release surface        instead of going away with the front surface. In practice,        however, such parts of the first layer, remaining on the release        surface instead of clinging to, and going away with, the first        surface, should be eliminated or at least minimised, for example        by suitable surface characteristics of the release surface        and/or by a suitable flexibility of the carrier and/or by a        suitable homogeneity in the sizes of the discrete particles        (i.e. by using a very narrow size interval of the discrete        particles). The removing of the tacky first layer from the hot        release surface includes a relative motion between the        (initially contacting) first layer and the release surface. The        direction of the relative motion, at least as long as the first        layer and the release surface are still in contact, is        preferably essentially perpendicular to the release surface, but        it is also possible to provide another direction. In an        industrial implementation both the carrier and the release        surface could travel with their respective line speeds and the        mentioned, essentially perpendicular, removing would correspond        to none of the carrier and the release surface being essentially        faster than the other. If, however, we need an essentially        non-perpendicular removing direction, we can provide one of the        speeds somewhat faster than the other or even an essential        lateral relative displacement can be provided between the        carrier and the release surface during the removing. The        mentioned essentially non-perpendicular removing can be used to        form an essentially non-isotropic structure of the coating, for        example a coating, including roughening projections inclining in        one direction, can be formed. Such a non-isotropic configuration        of the coating can be used for providing a non-isotropic        frictional behaviour of the product: for example the antislip        coated flexible material can show a lower friction against a        slip in one direction and an enhanced friction in the opposite        direction. Such a non-isotropic product could be used, for        example, as a roof underlayment on which an essentially        unidirectional walking friction is needed, or for another        example, as a geomembrane for lining an inclined ground surface        providing a non-slip engagement with a covering fibrous        geotextile for keeping the geotextile against gravity on the        slope. The hot first layer remaining on the front surface,        removed from the release surface, provides a hot coating on the        carrier. At forming the bond between the carrier and the coating        the utilising of the heat energy of the hot coating can        practicably mean that the whole heat energy that can be        conducted from the coating into the carrier is used to heat the        front surface and simultaneously as well as later both the        carrier and the coating are allowed to spontaneously cool. It is        also possible that a forced cooling is applied to the coating        and/or to the carrier, especially if the carrier is relatively        lightweight and the coating is relatively heavy. The bond formed        utilising the heat energy can be any kind of a bond needing the        heat, i.e., heat bond, for example, adhesive bond and/or fused        bond and/or welded bond etc. The forming of the bond is usually        completed when a cooling of the carrier and of the coating is        finished, for example when they cool down to ambient        temperature, though a considerable bonding strength can already        be provided in the formed bond well before the complete        cooling-down, depending on the kind, and parameters, of the        bond. It is also possible that the forming of the bond is        finished later than the mentioned cooling-down. The carrier,        provided with the coating bonded thereto, is made to constitute        an antislip coated flexible material. The coating can occupy the        whole front surface of the carrier, on the macro scale, but it        is also possible that the carrier has one or more places,        forming shapes, where the front surface has the coating, on the        macro scale. For example the coating can occupy one or more        stripes or spots in an endless carrier or one or more stripes or        spots in the outer surface of one or more side panels of a bag        on the macro scale. It is possible, for example, that the        coating includes a substance of a suitably high coefficient of        friction, for example, an elastomer, in which case even a        perfectly flat and smooth coating, formed for example by        strongly compressing the hot first layer, can be antislip.        Further, if, for example, the mentioned contacting includes        suitably low compressive pressures between the front surface and        the discrete particles of the first layer then the flexible        material can be made antislip by forming a suitable non-smooth,        i.e., rough, coating on it, with or without an elastomeric        substance in the coating. The rough coating can be formed to        include such roughening projections as provide an antislip        mechanical interlock with another similar roughened surface or        with a fibrous skidproofing material. As used herein, the word        “interlock” refers to a connection of parts in which the motion        of a part is limited and/or restricted by another. For a desired        configuration, for example, suitable sizes of the particles and        their suitable closeness, in the first layer, could be selected        in a suitable way. For example, if larger particles sit on the        release surface farther from each other then it is easier to        form a discontinuous, or rough final coating and if small        particles are distributed on the release surface with a great        surface closeness then it is easier to form a continuous final        coating. It is not required that the continuous coating be a        completely homogeneous coating, but it can even be formed with a        smooth flat surface. It can, however, help prevent the antislip        coated flexible material from blocking if the coating is not        perfectly smooth but inherits some of the discontinuous pattern        of the original first layer. Further, it is possible to apply a        relatively low compressive pressure, between the front surface        and the discrete particles, at a first place of the front        surface and a greater compressive pressure at another place of        the front surface in order to form areas of the antislip coated        flexible material with a coating of varied roughness and varied        thickness. That can be implemented, for example, by exerting the        compression in a nip, between two rolls, varying the compression        force in time, for example, periodically. The varying of the        compression force can, for example, be provided with varied        hydraulic compression and/or with providing, for example, at        least one of the niprolls with a compressing surface of varied        hardness along its perimeter. That can be used, for example, for        providing a film tube with a coating that is smoother (or        literally smooth) at places corresponding to tops and bottoms of        bags-to-be-formed, the coating being rougher therebetween, such        configuration possibly gaining utility, for example, in the        manufacturing of block-bottom valve bags. A selection of the        suitable thermoplastic second polymer includes, for example,        selecting a polymer having a viscosity, at the second        temperature, that suitably fits our objectives, regarding the        mentioned coating surface quality also with regard to the        selected way of contacting, for example, a pressure profile used        during the contacting. In general, for example, lower-viscosity        polymers are more suitable for forming a continuous, smooth        coating while higher-viscosity polymers are more suitable for        forming discontinuous coatings e.g., with specifically shaped        roughening projections. The removing of the carrier, from the        hot release surface, includes pulling the carrier out of the        contact with a pulling-out force. The pulling-out force is, for        example, in practice, substantially determined by a braking of        the carrier at the unwind but a tack, or adhesion, of the        carrier to the release surface, with the mediation of the first        layer, can also add to the pulling-out force. Generally the        pulling-out force should be selected at least a minimum        necessary for guiding the carrier and providing the desired        contact. The first temperature, of the provided hot release        surface, is provided above the softening temperature of the        second polymer, which helps to keep the first layer, of the        discrete particles, expressly hot and, thereby, tacky. Further,        the first temperature is also provided above any one or both of        a melting temperature and a softening temperature of the first        polymer. More over, the whole carrier is sensitive to the high        first temperature, namely the provided carrier is spoiled if        heated completely to the first temperature and simultaneously        exposed to the pulling-out force. The spoiling can happen for        example through one or more of breaking, stretching, shrinking        and warping. In practice, for example, as we experienced, if the        carrier has one or more base layers of polymer of a softening        temperature higher than the first temperature, the carrier can        still get spoiled through getting wrinkled, warped and        stretched, even broken, if exposed to the mentioned conditions,        because the softening or melting of the first polymer in the        carrier can weaken the carrier and can also release molecular        orientation in the first polymer, typically causing the warping.        The latter also holds, for example, for kraft paper coated with        the first polymer. In the method the carrier is therefore        protected from a harmful effect of the hot release surface,        which is based on selecting the contacting time shorter than a        minimum time, which minimum time is determined such that the        spoiling of the carrier by exertion of heat by the hot release        surface is limited to a predefined allowable extent, or is even        set such that the heat of the hot release surface does not spoil        the carrier. It means that the method can include limiting        spoiling effects of the heat of the release surface, exerted to        the carrier, to a predefined, for example unessential or even        zero, allowable extent by limiting the contacting time        accordingly. In practice, the skilled person can first decide        what an extent of distortion or warping or wrinkling or        shrinking or weakening etc. of the carrier can be allowed in a        given application e.g., such that the product can successively        be industrially used, or sold for industrial use, successfully.        Thus most generally, the invention method includes selecting a        carrier that is spoiled to a first extent, if heated completely        to the first temperature and simultaneously exposed to the        pulling-out force, and selecting the contacting time shorter        than minimally required by a heat of the hot release surface for        spoiling the carrier to the first extent. Generally, for        example, in case of a selected carrier that is spoiled through        breaking, if heated completely to the first temperature and        simultaneously exposed to the pulling-out force, a minimum        requirement could sound like the carrier should have sufficient        strength to be removed from the contact without breaking. For        that purpose, for example, the method could include selecting        the contacting time shorter than a minimum time which minimum        time is determined such that the spoiling of the carrier by        exertion of heat by the hot release surface is limited to a        predefined allowable extent thereby providing a strength of the        carrier sufficient for the carrier to withstand the pulling-out        force without breaking. Nevertheless, as we found, the method        can be readily suitable to prevent any impairment, whatsoever,        of the carriers used in practice. While it is of course        desirable that the contacting time is selected sufficiently        short that no spoiling of the carrier occurs, in practice        spoiling of the carrier to an unessential extent by exertion of        heat is acceptable in many industrial applications. There may be        a trade-off between a comfortably selected speed of the method        for forming an antislip flexible material and the extent of        spoiling the carrier by heat, but it is in the common knowledge        of people skilled in the art to select a minimum time such that        the spoiling of the carrier by exertion of heat by the hot        release surface is limited to a predefined allowable extent. The        contacting time can be set to a suitably low value for example        by trial and error: if the result of a trial is that the warping        or shrinking etc. is too strong then a shorter contacting time        must be tried. In a nip between two rolls practicably short        contacting times can easily be provided for trying, with trying        different line speeds. Harder niprolls, of smaller diameters,        can provide even shorter contacting times.

Advantages of the method include that it provides independence from amanufacturing of the flexible carrier itself; it can equally be used forfilms and fabrics; it is very flexible in selecting the parameters ofthe antislip coating; it does not need expensive equipment and rawmaterials; even recycled raw materials can be used in the coating; thecoating can be applied on a printed surface and/or the coated productcan be printed after its coating; it is flexible in its line-speed aslong as the contacting time is short enough (a “too short contactingtime” problem does practically not arise); the coating does notnecessarily essentially penetrate the carrier and can even be a sparsediscrete coating therefore it adds friction to a flexible materialwithout essentially compromising its strength, flexibility, heatshrinkability, isotropy of flexibility, and isotropy of heat shrinkingbehaviour; it is economical; it can provide antislip materials resistantto blocking. We note that, as used herein, a fusing, or welding, of thematerial of the coating with the material of the carrier we do notconsider to mean, in itself, that the coating, or an element of thecoating, penetrates, or enters, the carrier. The antislip coatedflexible material can be used in many non-packaging fields, for exampleas a roof underlayment, a geomembrane, a disposable sanitary coveringmaterial for the building industry, or in disposable sanitary underpadsin human health care or in veterinary medicine.

Preferably, in the method the contacting time is selected sufficientlyshort that the spoiling of the carrier through any one or more ofbreaking, stretching, shrinking, and warping is limited to at most anunessential extent. More preferably, the contacting time is selectedsufficiently short that the spoiling of the carrier is limited to atmost an unessential extent.

Even more preferably, in the method the contacting time is selectedsufficiently short that the carrier is prevented from being impairedthrough any one or more of breaking, stretching, shrinking, and warping.Even more preferably, the contacting time is selected sufficiently shortthat the carrier is prevented from being impaired.

Preferably, the provided flexible carrier is suitable for use as aflexible packaging or wrapping material. For example, for use inpackaging bags, including individual bags and FFS (form fill seal) bags,primarily for filling weights between 3.5 kg and 90 kg per bag, and forexample packaging wraps, including for example collation wrap, shrinkwrap, shrink hood, timber wrap, stretch wrap, stretch hood etc.

It is preferable, if the method includes the discrete particles being intheir entireties of or above the second temperature at the providing ofthe first layer. Its advantage is that it provides an even greater heatenergy for the bonding.

It is preferable, if the method includes providing the secondtemperature above any one or both of the melting temperature and thesoftening temperature of the first polymer. Its advantage is that itprovides an even greater heat energy for the bonding.

It is preferable, if, in the method, at least portions of the carrier,the portions including the first polymer, are prevented from melting orsoftening between the bringing into the contact and the forming of thebond. This should be achieved, for example, with selecting a suitablyshort contacting time. Its advantage is that it provides a betterproduct quality.

It is preferable, if the method includes

-   -   the provided carrier at least partly including a heat shrinkable        second layer including the thermoplastic first polymer,    -   at the providing of the carrier the carrier having a temperature        below a shrinking temperature of the second layer,    -   providing the first temperature above the shrinking temperature        of the second layer.

As used herein, “heat-shrinkability” in a direction shall mean, in thecontext of a material such as the second layer, that the material iscapable of being decreased in its length in the given direction, ordimension, in response to the transmission of thermal energy into thematerial. As used herein, the “shrinking temperature” of a materialrefers to the temperature at which the material, exposed to anincreasing temperature, starts to heat-shrink. The carrier, as mentionedearlier, can for example include a film as well as a fabric, for examplecoated or uncoated woven fabric.

Preferably the method further includes providing the carrier in originaldimensions thereof, and selecting the contacting time sufficiently shortfor preventing the carrier from contracting more than 25 percent(preferably more than 20 percent, more preferably more than 15 percent,more preferably more than 10 percent) from at least one of its originaldimensions. Its advantage is that it can provide antislip materials forusing in a shrink-wrap.

It is preferable, if, in the method, the antislip coated flexiblematerial is provided to have with itself an average blocking load lessthan 200 grams (preferably less than 150 grams, more preferably lessthan 100 grams, more preferably less than 80 grams, more preferably lessthan 60 grams, more preferably less than 50 grams, more preferably lessthan 40 grams, more preferably less than 30 grams) in a modifiedblocking load test. The modified blocking load test is defined asfollows. Two specimens of the material are to be tested with each other,with the antislip sides of the specimens facing each other. The modifiedblocking load test differs from the blocking load test defined in thestandard ASTM D 3354-96 in that the area of contact is 2.0 cm×5.0 cm=10cm², and the full back surfaces of both specimens are fixed to therespective aluminium blocks with double-coated tapes during the test,and the specimens to be tested shall be conditioned for 260 minutes at50° C.±2° C. compressed, face to face, with a pressure of 15900 Pa withthe full back surfaces of both specimens fixed to the respectivealuminium blocks with double-coated tapes. The mentioned pressure valuecorresponds to that arising at the bottom of a pallet load of deliveredantislip packaging bags, and the mentioned conditioning temperaturecorresponds to that arising in a storehouse or truck on a hot day. Thisfeature can be achieved using a relatively high-melting-point secondpolymer, exploiting the possibility to actually bond it at hightemperatures. Its advantage is that it provides high quality products,for example for packaging purposes. The result is that, for example,filled antislip bags or wrapped items, using our present antislipsolution, can be lifted up vertically from each other without extraefforts, and similarly, unused bags delivered flat, piled up on pallets,can be lifted up from each other easily, especially after a bending ofpackets of bags, for example back and forth, as is usual with allordinary (e.g. plastic or paper) packaging bags, before their use forfilling, to break up any blocking they might have.

It is preferable, if the method includes providing a carrier that losesits stability if heated completely to the first temperature. Thisfeature provides an even greater significance of the invention featureof the contacting time kept suitably short. Its advantage is that strongbonds, even welds, can possibly be formed.

It is preferable, if the method includes providing at least some of thediscrete particles having a size of at least 20 (preferably at least 25,more preferably at least 30, more preferably at least 35, morepreferably at least 40, more preferably at least 45) micrometres in atleast one dimension of the discrete particle. The mentioned dimensioncan, preferably, be the height. Its advantage is that a greater particle(with a given particle shape) provides a greater volume-to-surface ratioof the particle, thereby providing a greater efficiency of theutilisation of the heat energy as mentioned earlier. A theoretical upperlimit could be, for example, about 50 millimetres.

It is preferable, if, in the method a surface energy of the releasesurface is lower than a surface energy of the second polymer. Itsadvantage is that it helps remove the tacky first layer from the releasesurface without residue or with less residue.

It is further preferable, if, in the method a difference between thesurface energy of the second polymer and the surface energy of therelease surface is less than 23 mJ/m². Its advantage is that it helpsthe molten particles of the second polymer to somewhat wet the releasesurface in order of forming with the release surface suitably sharp, butnot too sharp first contact angles that could be advantageous in theforming of a discontinuous, roughening coating from the discreteparticles.

It is preferable, if, in the method a surface energy of the releasesurface is lower than a surface energy of the front surface of thecarrier. The surface energy of the release surface may be formed byknown materials and methods, such as siliconised surfaces,fluorochemicals, corona discharge, flame or the like.

It is further preferable, if, in the method a difference between thesurface energy of the front surface and the surface energy of therelease surface is greater than 4 mJ/m². Its advantage is that it helpsremove the tacky first layer from the release surface without residue orwith less residue, because the tacky first layer prefers to cling to thefront surface rather than to the release surface.

It is preferable, if, in the method the removing includes providing anadhesive force between the front surface and at least a majority of thecontacted tacky particles greater than an adhesive force between therelease surface and the at least a majority of the contacted tackyparticles. As used herein, a “majority” of the contacted tacky particlesmeans a number of the contacted tacky particles greater than half of atotal number of the contacted tacky particles. As used herein,“contacted tacky particle” means “tacky particle contacted by the frontsurface”. This can be achieved, for example, with selecting suitablesurface energies of the front surface and the release surface. Itsadvantage is that it helps remove the tacky particles, contacted by thefront surface, from the release surface without residue or with lessresidue, because the contacted tacky particles prefer clinging to thefront surface to clinging to the release surface.

It is further preferable, if, in the method the removing furtherincludes providing a cohesive force of the at least a majority of thecontacted tacky particles greater than the adhesive force between therelease surface and the at least a majority of the contacted tackyparticles. Its advantages include that it can result in a substantiallycomplete removing of the at least a majority of the contacted tackyparticles from the release surface. “Substantially complete” means thatat most 20% (preferably at most 15%, more preferably at most 10%, morepreferably at most 5%, more preferably at most 3%, more preferably atmost 2%) of the polymer of the at least a majority of the contactedtacky particles remain on the release surface during one removingoperation. This can be achieved, for example, with selecting a suitablygreat viscosity in the tacky particles. Its advantage is that itprovides greater control of the product quality. For example, it helpsto provide roughening projections more or less preserving in their topsthe shapes of the feet of the discrete particles, because a “pull away”effect, in which the polymer of the particles would be stretched in adirection perpendicular to the release surface, much like pulled taffy,can be essentially prevented. If a tacky particle should remain,un-removed, on the hot release surface and become old then later (forexample one revolution later, if the technology is based on a revolvingrelease belt or drum), when a new first layer is provided on the hotrelease surface, the adhesion force between the new first layerparticles and the old particle should be greater than an adhesion forcebetween the old particle and the release surface in order that the newfirst layer picks up and takes away the old particle. This is typicallypossible to provide, even with old particles (of, for example,polyethylenes), starting to oxidise. On the other hand, the old particlemay have an adhesive force, with the release surface, greater than newparticles have, due to a decomposition of the old particle. Therefore itshould be avoided to keep a first layer on the release surface too long(for example by an operator error) without a removing thereof.Nevertheless, those old particles, especially of polypropylenes, thattend to show a fast pyrolysis and therefore a stronger adhesion to therelease surface, can usually become fully decomposed and virtuallydisappear from the release surface as a fume and/or vapour. From suchfully decomposing polymer (for example, polypropylene) residues therelease surface can be cleaned in this automatic pyrolytic way.

It is preferable, if the method includes keeping the discrete particlesof the provided first layer sitting on the hot release surface longenough to provide at least some of the discrete particles in an at leastsemiliquid state and having first contact angles with the releasesurface. “At least semiliquid” means liquid or semiliquid. This can beachieved, for example, with using a sufficiently long endless belt forthe release surface on which the particles can spend enough time forsomewhat wetting the release surface the way described, and for lettingthe surface energies of the particles and the release surface mutuallyform the first contact angles. Its advantage is that it helps form acoating including separate roughening projections with flat tops whichis (among others) easier to write on or stick on a label and is smootherto the touch.

It is further preferable, if at least some of the first contact anglesare smaller than 90 degrees (preferably smaller than 85 degrees, morepreferably smaller than 80 degrees, more preferably smaller than 75degrees, more preferably smaller than 70 degrees, more preferablysmaller than 65 degrees). This can be achieved with giving the particlesa longer time to stay on the release surface and/or providing a lowerviscosity in the particles. Its advantage is that it helps to form anundercut in the roughening projections and/or to form rougheningprojections better interlocking with other similar rougheningprojections or a fibrous skidproofing material. On the other hand, thefirst contact angles can be selected to be greater than 30 degrees.

It is preferable, if, in the method an outer surface of the discreteparticles of the provided first layer is made up of a first portioncontacting the release surface and a second portion out of a contactwith the release surface, an area of the second portion being greaterthan an area of the first portion in at least a majority of the provideddiscrete particles. As used herein, a “majority” of the provideddiscrete particles means a number of the provided discrete particlesgreater than half of a total number of the provided discrete particles.This can be achieved for example by using a flat, smooth release surfaceor one with not too deep recesses. Its advantage is that it helps keepthe front surface away from, and possibly out of contact with, the hotrelease surface during the contacting time, in order to protect thecarrier from the heat of the exposed release surface parts between thediscrete particles.

It is preferable, if, in the method the provided hot release surface iseither essentially flat or it at most has a pattern independent from adistribution of the discrete particles of the provided first layer. Itsadvantage is that it helps to form a random distribution of the discreteparticles and also to provide a standing-out of the discrete particlesfrom the release surface for possibly keeping the front surface awayfrom the hot exposed release surface portions during the contactingtime.

It is preferable, if the method includes keeping the discrete particlesof the provided first layer sitting on the hot release surface for atleast 0.5 seconds, (preferably for at least 1 second, more preferablyfor at least 1.5 seconds, more preferably for at least 2.0 seconds, morepreferably for at least 2.5 seconds). This can be achieved, for example,with using a sufficiently long endless belt for the release surface. Itsadvantages include that it helps to suitably heat up the particles, andit helps the particles to lose some or all of their possible molecularorientations and to somewhat wet the release surface and to somewhat“smooth-out” or to get closer to a bead form in response to a surfacetension of the softened or molten polymer of the particles, which isadvantageous because, for example, it can provide the particles withmore uniform shapes. We note that it does not mean more uniform sizesthereof.

It is preferable, if, in the method the contacting time divided by anaverage surface mass of the carrier is provided to be at most 0.020s·m²/g, (more preferably at most 0.016, more preferably at most 0.013,more preferably at most 0.010 s·m²/g). “Average surface mass” of thecarrier means the mass of the carrier divided by the area of the frontsurface of the carrier. Its advantage is that it helps to protect thecarrier from an excessive heat of the release surface.

It is preferable, if, in the method the discrete particles of theprovided first layer sitting on the hot release surface project from therelease surface to respective particle heights, in at least some of thediscrete particles the particle height equalling at least 0.1 times(preferably at least 0.2 times, more preferably at least 0.3 times, morepreferably at least 0.4 times, even more preferably at least 0.5 times)a smallest top-plan-view extent of the particle.

It is further preferable, if the particle height, in at least a majorityof the discrete particles of the provided first layer, equals at least0.1 times (preferably at least 0.2 times, more preferably at least 0.3times, more preferably at least 0.4 times, even more preferably at least0.5 times) the smallest top-plan-view extent of the particle. As usedherein, a “majority” of the discrete particles of the provided firstlayer means a number of the discrete particles of the provided firstlayer greater than half of a total number of the discrete particles ofthe provided first layer. The smallest top-plan-view extent is thesmallest extent of the particle in a top plan view of the releasesurface taken from above the discrete particles (as if measured withsuch a caliper as is in the plane of the view). This feature,distinguishing the first layer from, for example, an ordinary printed-uplayer in a gravure printing process, has advantages including providinga greater volume-to-surface ratio of the particle, carrying a moreeffective heat charge and helping a forming of roughening projectionswith undercuts and/or of roughening projections better interlocking withother similar roughening projections or a fibrous skidproofing material,and helping in keeping the front surface away from, and possibly out ofcontact with, the hot release surface during the contacting time.

It is preferable, if the method includes providing, in the antislipcoated flexible material, an average surface mass of the coating lowerthan 1.5 times (preferably lower than 1.25 times, more preferably lowerthan 1.00 times, more preferably lower than 0.75 times, even morepreferably lower than 0.60 times) an average surface mass of thecarrier. The average surface mass of the coating is the mass of thecoating divided by the area of the carrier occupied by the coating (thearea also including possible interstices between discrete projectionsconstituting the coating). Average surface mass of the carrier means themass of the carrier divided by the area of the front surface of thecarrier. Its advantages, in addition to its economy, include that ithelps to keep the product flexible, and to prevent the carrier frombeing spoilt by an excessive heat energy of the coating, possibly evenwithout a forced cooling.

It is preferable, if the method includes providing an average surfacemass of the carrier less than 500 g/m² (preferably less than 420 g/m²,more preferably less than 370, or 320, 270, 220, 200, 180, 160, 140,130, or even 120 g/m²). A lowest limit of the average surface weightcould implicitly be determined, if necessary, for example, by the usagefor a packaging material and could be for example about 3 g/m². Suchselection increases the significance of the invention feature, asdiscussed in the recognition section above. Further, its advantages, inaddition to its economy, include that it can facilitate that theantislip coated flexible material can need less heat energy for itssubsequent fusing, welding and/or heat shrinking whose benefit is thatthe less heat energy will probably spoil, distort, melt or, for example,shrink the coating to a lesser extent.

It is preferable, if the method includes providing the heat energy ofthe hot coating suitably low for maintaining, without a need for achill-roll cooling, a breaking strength of the carrier sufficient for arewinding of the carrier. One possibility thereof, for example, is toprovide an (even expressly hot) coating of a suitably low surface masswith respect to a surface mass of the carrier.

It is preferable, if the method includes bringing portions of the secondpolymer onto the release surface at a release surface temperature abovethe softening temperature of the second polymer for providing the firstlayer of the discrete particles sitting on the release surface. Itsadvantage is that it eliminates a need for a repeated heating up andcooling down of the release surface with every revolution. Further, ithelps in fixing the discrete particles, from the moment they arrive atthe release surface, by heating them into a tacky state virtuallyimmediately.

It is further preferable, if the method includes any one or both of

a.) bringing onto the release surface from the air any one or more ofsolid, liquid and semi-liquid (though preferably solid) portions of thesecond polymer, and

b.) bringing onto the release surface, other than from the air,(preferably solid) portions of the second polymer colder than thesoftening temperature of the second polymer.

(We note that a portion of the second polymer can be colder than itssoftening temperature still other than solid for example in a solutionthereof) For example, second-polymer portions can be impacted from theair onto the release surface by gravity, electrostatic attraction,impaction or other suitable forces or any combination thereof.Dispersing of the second-polymer portions onto the release surface bygravity can be performed in any suitable way, for example, by scatteringsolid second-polymer portions with a scatter unit or spraying dropletsetc. On the other hand, for example solid second-polymer portions can befed onto the release surface directly from a feeder being in contactwith the release surface. Its advantage is that it avoids suchdifficulties as would possibly be involved if molten portions of thesecond polymer were to be transferred, by a positive contact with, forexample, a printing device, to the hot release surface. Namely, if therelease surface is such hot and in addition has desirable releaseproperties, then it would be difficult to fully transfer a melt fromanother, implicitly also hot, surface with sufficient certainty,especially if the viscosity of the molten second polymer is greater thenusual with hot melts applied with printing. If solid portions of thesecond polymer are brought onto the release surface then it provides theadvantage that the second polymer is only kept, during the whole method,in a hot molten or softened state for a very short time (unlike othersolutions based for example on melt extrusion and hot melt tanks) whichcan reduce a risk of oxidation or decomposition to a minimum even withcheap (possibly even recycled) second-polymer substances. Namely, theportions (for example, powder granules or micropellets) of the secondpolymer get in touch with the release surface and get heated up to meltand then, for example within a couple of seconds, they contact the frontsurface and cool down to solidify, which all can happen within, forexample, less than half a minute. The fact that the polymer only has tospend a very short time at the high temperature leads to the possibilityof using the desired, really high temperatures without decomposing oroxidizing the polymer too much. Further, bringing solid portions,instead of a hot melt printing, can allow much higher line speeds andlower melt mass flow rates in the second polymer. Preferably afluid-cooled heat shield is used to protect from radiant heat theapparatus used for bringing the portions of the second polymer to therelease surface with respect to the possible very high temperature ofthe release surface. For the same reason, it is preferable to protectthe arrangement from an undesired effect of a spontaneous hot airdraught generated by the hot release surface or of a hot air draftgenerated by the possibly high speed of the (for example, belt shaped)release surface.

It is preferable, if at least some of the discrete particles in theprovided first layer are essentially molecularly unoriented. It can beprovided, for example, by forming the first layer by scattering apowder, or similar material, of the second polymer onto the releasesurface, which powder, or similar material, is essentially molecularlyunoriented. It can also be provided, for example, by keeping thesoftened or molten discrete particles sitting on the release surfacelong enough for them to lose their possible molecular orientationthrough relaxing and/or free shrinking. Its advantages include that itcan help to form an antislip coated flexible material with a coatingessentially free of molecular orientation therefore not interferingwith, particularly not distorting in one direction, the original heatshrinking characteristics of the carrier. Further, such a coating, forexample including discrete roughening projections, can better keep itsown form during a subsequent heat shrinking of the antislip coatedflexible material.

It is preferable, if the method includes providing the first layer ofthe discrete particles sitting on the release surface with a randomdistribution. Its advantages include the following. It helps to form anantislip coated flexible material whose roughening projections are of arandom distribution which is known to be beneficial in regard of anisotropy of a mechanical interlock with another similar surface, and/orwith a fibrous skidproofing material, in the shearing direction.Further, if minute residues of the discrete particles are possibly lefton the (for example, belt-shaped) release surface after the removal ofthe tacky first layer from the release surface, then particles appliedin the next cycles will statistically sooner or later certainly hit themand possibly take them away from the release surface. Therefore thequality of the whole release surface in use will be homogeneous in thatrespect. Further, applying a true random pattern in the discontinuouscoating is a very good means of avoiding bumps formed in the rewoundantislip coated flexible material due to possible respective places ofthicker and thinner coating, or even a local lack of coating.

It is preferable, if the first layer is provided substantially free of atackifier.

The term “substantially free of a tackifier” here means that the firstlayer has less than about 5% by weight of a material commonly recognizedin the adhesive arts as a tackifier. As it is known, tackifiers areadded to adhesive formulations in order to increase the adhesionthereof. Materials commonly used as tackifiers include: rosin resins,cumarone-indene resins, terpene resins and hydrocarbon resins. Anadvantage of this embodiment is that it helps to avoid a blocking of theproduct in a warm storehouse. Further, it favours the use of cheaperpolymers.

It is preferable, if the method includes providing the carrier includinga fabric, and preventing the coating from essentially penetrating thefabric. As used herein, the coating is prevented from essentiallypenetrating a fabric made up of yarns, tapes and/or fibres, if thecoating is prevented from encapsulating a majority of the yarns, tapesand/or fibres being in contact with the coating. It can be provided for,for example, by selecting a suitably great viscosity of the secondpolymer and/or by selecting a suitably weak compression of the tackyfirst layer during the contacting, exploiting the fact that it is theheat energy that is primarily used for forming the bond between thecoating and the carrier and the bond is primarily a heat bond, ratherthan a mechanical-interlock-type bond based on a penetration of thecoating into the fabric. Its advantages include that it helps to keepintact the flexibility and heat shrinking characteristics of thecarrier.

It is preferable, if the coating of the antislip coated flexiblematerial is formed to be discontinuous. It can be achieved, for example,by a suitably moderate compression of the tacky first layer during thecontacting. Its advantages include that it can help prevent the antislipcoated flexible material from blocking, by providing a non-smoothcoating surface unsuitable to generate intimate contact with nearlycomplete exclusion of air along the surface. Further, it can helpcreating an antislip mechanical interlock with a suitable (e.g.roughened) other surface. Further, it can help preserve a flexibility ofthe carrier.

For the same advantages, it is further preferable, if the coatingoccupies at most 75% (more preferably at most 60%, or 50% or 40%, or35%, or 30%, or 25%, or 20%, or 17.5%, or 15.0%, or 12.5%, or 10.0%, oreven more preferably at most 8.0%) of an area of the antislip coatedflexible material in a top plan view. This is meant on the micro scale,wherein interstices in which the front surface is exposed are notconsidered to be occupied.

It is further preferable, if the coating is formed to include amultiplicity of discrete roughening projections projecting from thefront surface of the carrier, each roughening projection provided with afoot, the foot being an end of the roughening projection bonded to thecarrier.

It can be achieved, for example, by a suitably sparse distribution ofthe discrete particles in the first layer, in combination with asuitably moderate compression of the tacky particles during thecontacting. It is possible that a roughening projection is formed from asingle particle of the first layer, but it is also possible that aroughening projection is formed by joining a plurality of particles ofthe first layer, for example by a suitable compression of the firstlayer. Advantages of the method embodiment include that it can helpcreating an antislip mechanical interlock with a suitable (e.g.roughened or fibrous) other surface. Further, it can help preserve aflexibility of the carrier. Its economy, based on using less materialfor the coating, is also advantageous. It is also an advantage that theroughening projections can have a relatively smooth surface (includingfor example a smooth side), because the high temperature at which thecoating is kept can possibly smooth out a minor surface roughness of theindividual roughening projections, based on a surface tension of theirpolymer. This can improve an antislip interlock with other projectionsand particularly with fibres.

It is preferable, if the method includes providing at least some of theroughening projections with a second contact angle of between 90 and 178degrees (more preferably of between 92 and 178 degrees, more preferablyof between 95 and 178 degrees, more preferably of between 97 degrees and178 degrees) with the front surface in at least one side view of theroughening projection. As used herein, a side view means anon-perspective view taken from a direction generally parallel with thefront surface, for example a view taken from the left, or from theright, during a horizontal orientation of the front surface. The viewincludes the roughening projection as well as (a side section of) atleast that part of the front surface with which the second contact angleis formed. Here the term “second contact angle” is used in a senseanalogous with as if the roughening projection was a drop of liquidsitting on the solid front surface: as used herein, the second contactangle is the angle, measured through the roughening projection, closedbetween the roughening projection—air interface and the front surface ofthe carrier where the roughening projection—air interface meets thefront surface. In practice, that can be observed under magnification.This feature can be provided, for example, by applying a moderatepressure to the tacky discrete particles, of a suitably great viscosity,during the contacting time, while simultaneously providing for an easyrelease thereof from the release surface. For example this featuredistinguishes our solution from known methods in which a coating is madeby printing a layer of (typically low-viscosity and well-wetting) hotmelt onto a surface. Advantages of the method embodiment include that ithelps to provide the roughening projections with an undercut which makesthem more suitable for an antislip mechanical interlock, in the shearingdirection, with similar roughening projections of a facing surface, orwith a fibrous skidproofing material.

It is preferable, if the method includes providing at least some of theroughening projections with a substantially flat top forming an edge atleast partially surrounding the substantially flat top. We note that theflat top does not just mean a top that is flat in a side view thereof,but it means that the roughening projection has a top area that isessentially flat. It is not necessary but preferable if planes of theflat tops are essentially parallel with each other, and, preferably,also essentially parallel with the front surface. It can be provided,for example, by applying a moderate pressure to the tacky discreteparticles, of a suitably great viscosity, during the contacting time,while simultaneously providing for an easy and essentially perpendicularrelease thereof from the release surface. Its advantages include thatthe product can be easier to write on with a pen and/or to stick on aself-adhesive label or tape, the product can feel smoother to touch. Theproduct can be subsequently provided with a more beautiful printedimage. Further, as the flat tops can together provide a substantialabutting surface, the antislip coated flexible material can have animproved friction on smooth surfaces even without ahigh-coefficient-of-friction substance in the roughening projections.And if the substance of the roughening projections has a highcoefficient of friction (for example, an elastomer) then the antislipeffect thereof can be more emphasized or more significant, due to anincreased total surface on which it can abut a smooth surface. Theresult is an improved combination of a friction based on an elastomericsubstance and a friction based on a mechanical interlock of theroughening projections. The presence of the edge can, for example,facilitate the mentioned mechanical interlock.

For the same advantages, it is further preferable, if the methodincludes providing at least a majority of the roughening projectionswith a substantially flat top. As used herein, a “majority” of theroughening projections means a number of the roughening projectionsgreater than half of a total number of the roughening projections.

It is further preferable, if the method includes the edge completelysurrounding the substantially flat top. Its advantages include that itcan help to better interlock in all directions.

It is further preferable, if the method includes the edge essentiallyforming a circle. Its advantages include that it can help to furtherincrease the isotropy.

It is further preferable, if the method includes in at least one sideview of the roughening projection at least one part of a contour line ofthe roughening projection, connecting the foot and the edge, beingconvex from outside. The contour-line part mentioned is that part of thecontour line which connects the foot and the edge, and it can forexample be at a right side or a left side of the roughening projectionin its at least one side view during a horizontal orientation of thefront surface. It means that it is convex when looking from the outsideof the roughening projection. As used herein, and in accordance with themathematical meaning of the word, the contour-line part forms theboundary of a convex set of points, the points belonging to theroughening projection; a “convex contour-line part” includes the case ofa straight contour-line part, too.

It is further preferable, if the at least one contour line part isstrictly convex from outside. As used herein, a strictly convexcontour-line part of a roughening projection, in a side view is convexwhen looking from the outside and not straight. A (preferably strictly)convex shape (preferably convex in more side views, more preferably inall side views) of the roughening projection contour-line part has beenfound to be beneficial because it gives a relatively large thickness tothe roughening projection. This convex shape provides strength to theedge. A convex shape also effectively leads engaging fibres down towardsthe carrier, thereby reducing torque load on the roughening projectionsand the carrier where they are attached (i.e., at the foot).

It is further preferable, if the method includes in at least one sideview of the roughening projection a ratio of a width of thesubstantially flat top to a foot width being from 0.50 to 1.24.(Preferably from 0.8 to 1.24, more preferably from 0.9 to 1.24, morepreferably from 1 to 1.24, more preferably from 1 to 1.20, morepreferably from 1 to 1.18, more preferably from 1 to 1.15, even morepreferably from 1 to 1.10.) Its advantages include that the ratio beinggreater than 0.50 can help exploiting advantages from there being a flattop and can help providing an engagement with an engaging fibre of askidproofing material as well as with similar, facing projections. Onthe other hand, the ratio being lower than 1.24 can help keep anundercut of the roughening projection moderate enough to allow an easy,practically effortless separation of the antislip coated flexiblematerial from a fibrous skidproofing material in a lifting or peelingoperation in order to avoid an undesired lifting or peeling strength,known for example from hook and loop fasteners, of the antislipinterlock.

It is further preferable, if the method includes an area of the footbeing essentially equal to, or smaller than, an area of thesubstantially flat top. Advantages include that it helps to give to theroughening projections a form with an undercut, or a form in which thewidest (i.e., widest-in-side-view) part, or the part of maximum sidewardbulge, is closer to the top than to the foot, which makes the rougheningprojections more suitable for an antislip mechanical interlock, in theshearing direction, with similar roughening projections of a facingsurface, or with a fibrous skidproofing material. The advantages furtherinclude that it can help to use the flat top's edge for the mechanicalinterlock, either with another similar roughening projection or with afibrous skidproofing material. Its particular advantage is that theinterlocking parts do not necessarily have to be pressed very close toeach other, because already the farthest point, the top, of theroughening projection can be able to establish the interlock. This has agreat significance as soon as the front surface is contaminated withdust or snow from which the interlocking parts can stick out, or if theroughening projection stands out of a depression of the front surface,for example as a result of the roughening projection having beenimpressed.

For the same advantages, it is further preferable, if the methodincludes the area of the foot being smaller than the area of thesubstantially flat top. It can be provided, for example, by keeping thediscrete particles sitting long enough on the hot release surface togive them a form similar to cups turned with their mouths toward therelease surface, and applying a gentle compression during the contactingand providing an easy release of them from the release surface.

It is further preferable, if the method includes providing theroughening projection with an edge angle being an angle, measuredthrough the roughening projection, closed between the substantially flattop and a mantle surface extending from the edge to the foot. In otherwords, the edge angle is the angle that the top, and the side of theprojection attaching to the top at the edge, close with each other atthe edge. Its advantages include that it can help make the antislipinterlock of the edge of the top more significant.

It is further preferable, if the method includes providing theroughening projection with the edge angle essentially equal to, orsmaller than, 90 degrees, in at least one side view of the rougheningprojection. It can be provided, for example, by keeping the discreteparticles sitting long enough on the hot release surface to provide themwith acute first contact angles with the release surface and thensufficiently preserving that geometry of the particles during thecontacting and removing. The advantage of such an antislip rougheningprojection is that the edge of the flat top, being essentially in theplane of the top and forming the edge angle, can readily enter into, andengage with, a fibrous skidproofing material without a need fordisplacing a substantial volume of the fibrous skidproofing material.Similarly, the elevated position of the “sharp” edge makes it easier forthe edge to interlock with another similar roughening projection, oreven with a sole of a boot of a worker walking on a block of timber,wrapped in the antislip coated flexible material. The interlockingeffect can be provided even if the roughening projection has its foot ina depression of the front surface, therefore the antislip capabilitiesof the product can be maintained even if the roughening projections aresomewhat impressed into the front surface or are in some other wayplaced in respective depressions or indentations of the front surface.Further, this has a great significance as soon as the front surface iscontaminated with dust or snow or ice from which the interlocking edgescan stick out.

For the same advantages, it is further particularly preferable, if theedge angle is smaller than 90 degrees, (preferably smaller than 87degrees, more preferably smaller than 84 degrees, more preferablysmaller than 81 degrees, more preferably smaller than 78 degrees). Onthe other hand, it can be selected to be greater than 30 degrees toprovide a suitable strength of the edge. It is preferable, if the methodincludes forming at least one side view of the roughening projectiontapering from the edge to the foot. (Preferably a plurality of sideviews, more preferably all side views of the roughening projectiontaper.) As used herein, tapering to the foot means becomingprogressively narrower or remaining of the same width toward the foot.For example, a cylinder is a tapering shape (though not a strictlytapering shape). Its advantages include that this type of tapering willhelp pull engaged fibres down to the front surface of the carrier when ashear load is applied to the antislip interlock without the fibres beingcaught at a non-tapered portion displaced from the front surface. Thusthe torque on the roughening projection is minimal so the carrier can beweaker, i.e., can be cheaper, more flexible, thinner etc. Furthermore,the product may have a relatively large surface area formed by thesubstantially flat tops, making the product smooth to the touch and easyto stick on a label or tape or to write on, while also having arelatively low total surface area of the projection feet connected tothe carrier, increasing the flexibility of the product. Further, thisfeature is advantageous as soon as the front surface is contaminatedwith dust or snow from which the interlocking, widest parts can stickout.

For the same advantages, it is further particularly preferable, if themethod includes forming each side view of the roughening projectiontapering from the edge to the foot. Advantages include an improvedisotropy of the product.

For the same advantages, it is further particularly preferable, if theside view strictly tapers from the edge to the foot. As used herein,strictly tapering to the foot means becoming progressively narrowertoward the foot. For example, a suitably oriented truncated cone is astrictly tapering shape.

It is preferable, if the method includes forming the rougheningprojections with a random distribution in a top plan view of theantislip coated flexible material. As used herein, random distributionrefers to the distribution on the micro-scale. Its advantages includethat an antislip interlock between two such surfaces facing each othercan be independent of a relative orientation of the facing surfaces.

It is preferable, if the method includes forming the rougheningprojections of random top-plan-view sizes. Advantages include that itcan help the product to be more universal. Namely, ability of aroughening projection to enter between and well engage with interstices,between projections of a mating roughened surface or even between fibresof a mating skidproofing material, can depend on the top-plan-view sizeof the roughening projection. Namely, a smaller roughening projectioncan best fit into one kind of interstice while a bigger rougheningprojection can fit into another kind of interstice. It means that anantislip coated flexible material having roughening projections ofvarious sizes can possibly more universally engage, with many kinds ofmating surfaces.

For analogous advantages, it is preferable, if the method includesforming the roughening projections of random orientations in a top planview of the antislip coated flexible material. As used herein,orientation of a roughening projection in a top plan view does not referto a molecular orientation of the polymer of the roughening projectionbut to its angular position.

It is preferable, if the method includes forming such rougheningprojections as project from their respective feet to respectiveprojection heights and as have respective smallest top-plan-view extentsand within at least a majority of the roughening projections acoefficient of variation of the smallest top-plan-view extents isgreater than a coefficient of variation of the projection heights. Asused herein, the smallest top-plan-view extent of a rougheningprojection means its smallest extent in the top plan view, as wementioned earlier.

It is further preferable, if the coefficient of variation of thesmallest top-plan-view extents is at least 1.15 times (preferably atleast 1.2 times, more preferably at least 1.3 times, more preferably atleast 1.4 times, more preferably at least 1.5 times, more preferably atleast 1.6 times, more preferably at least 1.7 times, more preferably atleast 1.8 times, more preferably at least 1.9 times, more preferably atleast 2.0 times) the coefficient of variation of the projection heights.

It can be provided, for example, by using a powder for making thediscrete particles of the first layer, and letting the inherentirregularity of the sizes, or volumes, of powder granules appear in thevaried smallest top-plan-view extents of the roughening projections bycompressing the hot particles of the first layer to a more or less evenprojection height during the contacting. We note that the tops of theroughening projections can be, for example, flat or can be structuredwith a regular and/or irregular and/or random and/or other structure,and/or can have a pattern essentially inherited from a surface patternof the release surface. Advantages are based on our recognition asfollows. Ability of a roughening projection to enter between and wellengage with interstices, between projections of a mating roughenedsurface or even between fibres of a mating skidproofing material, candepend on the smallest top-plan-view extent of the rougheningprojection. Namely, a “narrower” (i.e., narrower in the top plan view)roughening projection can fit into one kind of interstice while aroughening projection of a greater “smallest top-plan-view extent” canfit into another kind of interstice. It means that an antislip coatedflexible material having many kinds of roughening projections, ofvarious “smallest top-plan-view extent” values, can possibly moreuniversally engage, with many kinds of mating surfaces. Therefore arelatively great coefficient of variation of the smallest top-plan-viewextents can be beneficial. On the other hand, as we could see, a more orless uniform height of the roughening projections can help to provide agreater abutting surface (and thereby a better friction) on smoothsurfaces and also to provide more of the roughening projections gettinginvolved in engaging with the mentioned structured mating surfaces.Therefore a relatively low coefficient of variation of the projectionheights can be beneficial.

It is preferable, if the method includes tops of at least a majority ofthe roughening projections essentially being in alignment along a planeparallel with a general plane of the front surface. As used herein, thetop of a roughening projection means a point, or part, of the rougheningprojection farthest above the general plane of the front surface. Thegeneral plane of the front surface may not contain some points of thefront surface, for example points of an indentation or bump of the frontsurface. For example in the case of a front surface of a woven fabriccarrier the general plane of the front surface can represent an averageof the (possibly mathematically non-planar but technically generallyplanar) woven surface. It is possible, for example, that the mentionedaligning tops are flat surfaces, but it is also possible that they arerespective single points of the respective roughening projections,depending on respective shapes of the roughening projections. It can beprovided for, for example, by compressing the first layer into asubstantially uniform thickness before the removing. Advantages of thementioned method embodiments include that the product, possiblypreserving the benefits of a random character of its rougheningprojections, can be easier to write on with a pen and/or to stick on alabel or tape, the product can feel smoother to touch. The product canbe provided with a more beautiful printed image. Further, as theroughening projections of a more or less uniform height can togetherprovide a substantial abutting surface, the antislip coated flexiblematerial can have an improved friction both on smooth surfaces and withanother roughened or fibrous engaging surface.

It is further preferable, if the method includes forming such rougheningprojections as project from their respective feet to respectiveprojection heights and providing, in at least some of the rougheningprojections, a smallest top-plan-view extent of the rougheningprojection equalling at least 1.75 times (preferably at least 1.8 times,more preferably at least 1.9 times, more preferably at least 2.0 times,more preferably at least 2.1 times) the projection height.

This can be provided, for example, by a suitably strong compression ofthe tacky first layer during the contacting. Its advantage is that sucha wide roughening projection will not tend to break off too easily. Forthe same reason, it can be resistant to leaning to the side, around itsfoot, in response to a shearing load thus keeping its interlockingcapacity. If necessary, a theoretical maximum ratio could, for example,be defined as the smallest top-plan-view extent equalling at most 5000times the projection height.

It is preferable, if during the contacting time a portion of the frontsurface, between neighbouring tacky particles, is kept out of a contactwith the release surface. It can be provided for, for example, by usinga second polymer of a suitably high viscosity simultaneously withproviding a suitably gentle compression during the contacting. That waythe discrete particles can be prevented from being pressed too flat, andthey together can keep the front surface at a positive distance from thehot release surface, especially if the closeness of the discreteparticles is great enough for the purpose also with regard to aflexibility of the carrier. This feature is particularly advantageous incombination with heights of at least some roughening projections beingat least 20, or more preferably 30, or more preferably 40 micrometres.Its advantages include that it decreases the heat energy transferred(for example, radiated) into the carrier directly from the hot releasesurface.

It is preferable, if the method includes providing at least some of theroughening projections with a hidden surface portion being a portion ofan outer surface of the roughening projection which the rougheningprojection covers from a viewer in a top plan view of the antislipcoated flexible material taken from above the roughening projections. Asused herein, the outer surface of the roughening projection isessentially the roughening projection—ambient air interface, which inpractice can mean a surface of the roughening projection that can beseen from somewhere, and for example the foot of the rougheningprojection, where it attaches to the carrier is not a part of the outersurface of the roughening projection and therefore it is not a hiddensurface portion either. Thus the hidden surface portions of a rougheningprojection can be found with finding out what parts of the projection'souter surface are invisible, in the top plan view, because of beinghidden, from the viewer, by the projection itself. For the forming ofsuch roughening projections various techniques, mentioned so far, can beused. Its advantages include that it helps to give to the rougheningprojections a form with an undercut which makes them more suitable foran antislip mechanical interlock, in the shearing direction, withsimilar roughening projections of a facing surface, or with a fibrousskidproofing material.

It is further preferable, if the at least some of the rougheningprojections have at least one undercut and include at least one areaimmediately above the undercut, the roughening projection being sodimensioned as to form a separation between the at least one area andthe front surface which is greater than 10 micrometres (preferablygreater than 12 micrometres, more preferably greater than 15micrometres, more preferably greater than 20 micrometres). We note thatthe mentioned at least one area can, in a given case, be constituted bythe edge alone. Its advantages include that it helps to maintain aninterlocking capacity of the roughening projections even if acontaminating layer (for example, of white frost or fine dust) builds onthe front surface, at least as long as the thickness of thecontaminating layer does not reach the size of the mentioned separation.

It is preferable, if the method includes providing two nip rolls andpressing the carrier toward the hot release surface within a nip betweenthe two nip rolls to provide the contact between the front surface ofthe carrier and the tacky terminal ends of the particles sitting on thehot release surface, exerting on the carrier a nip pressure between0.001 and 80 N/lineal cm (preferably between 0.002 and 70 N/lineal cm,more preferably between 0.005 and 60 N/lineal cm). We note that thisinterval includes values much lower than usual in background-artnip-pressure values. Its advantages include that, providing practicablevalues of such process parameters as discrete particle size andcloseness, second polymer viscosity and first and second temperatures,its nip pressure interval can provide advantageous products mentionedabove. Low nip pressures do not necessitate such expensive machinery asgreat nip pressures. It is preferable to select a width of the rollpressing the carrier smaller than a width of the carrier because thatway the whole roll can be kept cool, due to the carrier possibly beingprevented, for example by the suitably high line speed, from heatingthrough too much.

It is preferable, if the method includes utilising the heat energy ofthe hot coating of the discrete roughening projections for heating partsof the carrier near at least some of the roughening projections,sufficiently to soften or melt at least the first polymer in the heatedcarrier parts, and thereafter allowing the carrier and the rougheningprojections to cool into a solid state for forming a final bond. Itmeans that the heat bond can be formed with such great heat energy thatcan actually locally soften or melt, at least partly, the carrier. Forexample the mentioned parts can be portions of the carrier close to feetof discrete roughening projections. For example it is possible that awall of the carrier is locally softened or melted in its full thickness,or in a part of its thickness, under the foot of the rougheningprojection. It is possible that the roughening projection directlycontacts the first polymer of the carrier but it is also possible thatthe front surface of the carrier, contacted by the rougheningprojection, is constituted, for example, by a thin, printednon-thermoplastic layer (of customer graphics, for example), in whichcase the heat, softening or melting the portion of the carrier, istransferred through the thin printed layer without melting the printedlayer itself “Allowing to cool” can, for example, refer to a spontaneouscooling as well as to a forced cooling or to a combination of both.Advantages include that such bonds, made with great local heat energies,can be stronger and the product can be more resistant to blocking (in awarm storehouse) than others. Further, the carrier can be prevented frombeing spoiled, despite the fact that parts of it get softened or melted.This can be provided for, for example, by selecting a suitably smallsize and/or low closeness of the discrete roughening projections, withregard to their temperature.

It is preferable, if the method includes providing both the firsttemperature and the second temperature above a fusing temperature atwhich the first polymer and the second polymer are capable of fusingtogether. Its advantages include that bonds made at such hightemperatures can be stronger and can provide more resistance to blocking(in a warm storehouse) than others (for example those with an ordinaryhot melt adhesive).

It is preferable, if the method includes providing the first temperatureabove 130° C. (preferably above 140° C., more preferably above 190° C.,more preferably above 200° C., more preferably above 205° C., morepreferably above 210° C., more preferably above 215° C.).

It is further preferable, if the method includes providing the secondtemperature above 130° C. (preferably above 140° C., more preferablyabove 190° C., more preferably above 200° C., more preferably above 205°C., more preferably above 210° C., more preferably above 215° C.). It,essentially, can provide for a charge of heat energy in the first layerthat is (preferably far) greater than enough for just keeping the firstlayer molten or softened: it is also capable of considerably heating upthe contacted front surface in order that the forming of the bondincludes significantly heating up both of the bonded parts. Advantagesinclude that such bonds, made with such high temperatures, can bestronger and can provide more resistance to blocking (in a warmstorehouse) than others (for example than those with an ordinary hotmelt adhesive).

It is further preferable, if the method includes providing both thefirst temperature and the second temperature below 300° C. This can helpto prevent the carrier from being spoilt from an excessive heat of thecoating.

It is preferable, if the method includes providing the first temperatureat least 30° C. degrees higher (preferably at least 40° C. degreeshigher, more preferably at least 50° C. degrees higher, more preferablyat least 50° C. degrees higher, more preferably at least 60° C. degreeshigher, more preferably at least 70° C. degrees higher) than both thesoftening temperature of the second polymer and at least one of themelting temperature and the softening temperature of the first polymer.This has the advantage that it provides a suitable forced heating forcreating a high-temperature bond.

It is preferable, if the method includes providing the second polymer ofa melt mass flow rate of 0.1 to 300 g/10 min (preferably 0.1 to 250 g/10min, more preferably 0.1 to 200 g/10 min, more preferably 0.1 to 150g/10 min, more preferably 0.1 to 100 g/10 min, more preferably 0.1 to 80g/10 min, more preferably 0.1 to 60 g/10 min, more preferably 0.1 to 40g/10 min, more preferably 0.1 to 30 g/10 min, more preferably 0.1 to 20g/10 min, more preferably 0.1 to 10 g/10 min) determined at 190° C.under a load of 2.16 kg in accordance with ISO 1133-1. Advantagesinclude that a melt of such polymers (typically having a viscosity muchgreater than a typical viscosity of a hot melt applied with printing)can possibly be removed from the hot release surface without a cohesivefailure, i.e., without a splitting of the melt due to a too low cohesiveforce in the melt. Further, such a suitably selected melt mass flow ratecan provide a viscosity of the discrete particles suitable for theforming of the preferred roughening projection configurations. Namely,the selected value range can provide a viscosity in the discreteparticles, sitting directly on the hot release surface for a certaintime, low enough for the discrete particles to suitably wet the releasesurface forming therewith desirably sharp, preferably acute, firstcontact angles. This feature, of having a viscosity low enough, canfurther improve with selecting even higher melt mass flow rate values(for example 0.5 or 1.0 or 1.5 or even 2.0 g/10 min) in the lower limitof the value range. On the other hand, the same selected value range canprovide a viscosity in the discrete particles, (e.g., gently) pressedfor a very short time to the cold front surface, high enough forpreventing the discrete particles/roughening projections from wettingtoo much the cold front surface during the contacting time andafterwards as long as they are hot at all, this possibly resulting indesirable obtuse second contact angles of the roughening projectionswith the front surface. Similarly, the high-enough viscosity can preventthe discrete particles/roughening projections from losing too much oftheir original, preferably cup-like shape which they were provided withwhen they stayed on the release surface. This feature, of having aviscosity high enough, further improves with selecting even lower meltmass flow rates in the upper limit of the value range. Further, thelower the melt mass flow rate of the second polymer, the better theroughening projections will keep their original forms (against aspontaneous bead-forming) when they get external heat, for exampleduring a fusing or welding of the product or in a heat shrinking of theproduct, or when hot contents are filled into the bag made from theproduct. Further, the melt mass flow rate being greater than 0.1 g/10min can help to provide an easy sealability, weldability of the product,namely when the roughening projections happen to be between sealing orwelding tools during a sealing or welding then they can become pliablycompressible enough not to remain “spacers” keeping the welding toolsfrom abutting. This feature can also further improve with selecting thementioned even higher melt mass flow rate values in the lower limit ofthe value range.

It is preferable, if the method includes providing one or both of themelting temperature and the softening temperature of the first polymereither lower than or equal to or at most 50° C. degrees higher than thesoftening temperature of the second polymer. This has the advantage thatit provides a possibility of a high-temperature bond in respect of thefirst polymer. Its advantage over other bonds (for example, with bondswith an ordinary hot melt adhesive) is that such bonds are stronger andthe product will not block.

It is preferable, if the method includes providing at least a majorityof the roughening projections with a top-plan-view size of at least 30micrometres and at most 40 millimetres (preferably of at least 40micrometres and at most 20 millimetres). Advantages include thatroughening projections of such size are large enough for providing anantislip mechanical interlock and small enough to preserve a suitableflexibility and heat-shrinkability of the carrier.

It is preferable, if the method includes providing, in the antislipcoated flexible material, such roughening projections whose averagetop-plan-view aspect ratio is at least 1.0 and at most 20.0 (preferablyat most 19.0, more preferably at most 18.0, more preferably at most17.0, more preferably at most 16.0, more preferably at most 15.0, morepreferably at most 14.0, more preferably at most 13.0, more preferablyat most 12.0, more preferably at most 11.0, more preferably at most10.0, more preferably at most 9.0, more preferably at most 8.0, morepreferably at most 7.0, more preferably at most 6.0, more preferably atmost 5.0, more preferably at most 4.0, more preferably at most 3.0, morepreferably at most 2.0, even more preferably at most 1.75). Eachroughening projection has its own top-plan-view aspect ratio which meansa ratio of the greatest to the smallest extent of the rougheningprojection in a top plan view of the antislip coated flexible materialtaken from above the roughening projections. The average of thetop-plan-view aspect ratio values of each of the multiplicity of theroughening projections is at most 20.0, which means it is either 20.0 orless than 20.0. Its advantages include that a lower averagetop-plan-view aspect ratio value provides, in the antislip coatedflexible material, a greater flexibility with a greater isotropy of theflexibility, and a greater heat-shrinkability with a greater isotropy ofthe heat-shrinkability. Further, discrete particles with higher averagetop-plan-view aspect ratio values (for example, oblong filaments) aremore difficult to bond to the carrier at a given desirably hightemperature without spoiling the carrier than discrete particles withlower average top-plan-view aspect ratio values (for example, powderparticles), the latter only possibly melting the carrier in small,dot-like spots which possibly does not spoil the carrier like a meltingof the carrier along an oblong spot.

It is preferable, if the method includes providing the carrier includinga fabric woven from overlapping warp and weft thermoplastic tapes oryarns, and selecting the utilised heat energy, of the hot coatingincluding the roughening projections, suitably for forming the bondbetween the carrier and the roughening projections without fusingtogether the overlapping warp and weft tapes or yarns under at leastsome of the roughening projections. This can be achieved by a setting ofthe manufacturing parameters, for example, by trial and error. The heatenergy of a hot roughening projection depends on, and can be modifiedwith a modification of, any of the temperature of the hot rougheningprojection, a mass of the roughening projection and a specific heat ofthe roughening projection. It is also possible to select a fabric oftapes (or yarns) of a suitable heat sensitivity, for achieving thedesired result. Advantages include that it preserves a flexibility andheat shrinkability, as well as an isotropy thereof, in the woven fabriccarrier.

It is preferable, if the method includes providing the carrier includinga fabric woven from plastic tapes, the tapes exposed at least in a partof a surface of the carrier, and providing in the antislip coatedflexible material at least one (preferably: at least some) of theroughening projections having suitable geometric features with respectto the exposed tapes for forming with at least one of the exposed tapesa slip-decreasing mechanical interlock. An example for exposed tapescould be tapes not covered by a coating in the carrier. The suitablegeometric features will depend on what the exposed tapes are exactlylike, but usually roughening projections having substantially flat topswith edge angles smaller than 90 degrees are able to catch, with their“sharp” edges, edges of overlapping warp or weft tapes of a wovenfabric, especially if the fabric includes exposed twisted tapes meantfor enhancing its friction. Such catching of the tape edges or a littlepenetration between the overlapping tapes can be enough to decrease theslip between a roughened front surface and an exposed fabric part. Thetapes can be exposed in the front surface and/or in a back surface ofthe carrier, or, for example if the carrier is provided in the form of atubular woven fabric, the tapes can be exposed in an inner side of thetube while the front surface is on the outer side. The advantagesinclude that such a contact, of decreased slip, can be utilised forexample between fabric bags, filled for example with flour, put on topof each other, or between overlapping fabric parts for example in atimber wrap, or between overlapping reel-ends (potentially even betweenoverlapping tube-ends one pushed inside the other in a telescopic way)at a reel-changing in any process rewinding or processing, and changing,reels of such a roughened fabric for example in a tube form or in asingle-wound-sheet form. Namely, when at a reel change the ends of therespective reels of fabrics must be fixed to each other, so that one canpull the other, it is advantageous if the fixing is helped with thementioned slip-decreasing mechanical interlock, also with regard to thefact that a fixing of the reel ends to each other with a self adhesivetape can be made somewhat more difficult by the fact that the surface(s)to tape can be roughened.

It is preferable, if the method includes providing the antislip coatedflexible material capable of a slip-decreasing mechanical interlock in ashearing direction with a skidproofing material, of an ordinarypolypropylene spunbonded nonwoven fabric of an average surface mass of17 g/m² and filament thickness of between 25 and 30 micrometres, due tothe roughening projections having suitable closeness and geometricfeatures with respect to the skidproofing material for formingmechanical bonds with the filaments of the skidproofing material in theshearing direction. “Ordinary” means that the skidproofing material doesnot differ essentially from commodity nonwovens, of similarspecification, commonly used, for example, in the hygiene industry atthe time of the current application (including, for example, that it isnot hydrophilic, it is un-coated, un-printed, un-creped, and it is notnapped). A photograph of a sample of the specified nonwoven can be foundamong the figures.

It is further preferable, if a static friction between two specimens ofthe antislip coated flexible material, with a specimen of theskidproofing material placed between the specimens of the antislipcoated flexible material, is suitably high to resist sliding in aninclined-plane-type static-friction test of 50 degrees angle (preferablyof 55 degrees angle, more preferably of 60 degrees angle, morepreferably of 65 degrees angle) according to the TAPPI T 815 standard.The two specimens of the antislip coated flexible material must faceeach other with their coatings. All three specimens must be smooth, notwrinkled. As it is known, in this test, 50 degrees correspond to astatic coefficient of friction (C.O.F.) of 1.19, while, for example, 65degrees mean a C.O.F. of 2.14, which are considerably great values inthe art.

It is further preferable, if the static friction is suitably high toresist the sliding immediately after a preparation, the ice testpreparation, the ice test preparation including maintaining in at leastthe carrier front surface, and the coating, of a first one of the twospecimens of the antislip coated flexible material a third temperatureof between −15° C. and −25° C. while exposing the carrier front surfaceand the coating to air of a temperature of between 0° C. and 4° C. andof a relative humidity of 100% for a preparation time of 3 minutes(preferably of 5 minutes, more preferably of 8 minutes) and the ice testpreparation further including providing a second one of the twospecimens of the antislip coated flexible material and the specimen ofthe skidproofing material of the third temperature. The ice testpreparation can be used to simulate a situation possibly arising duringa use of bags of the antislip coated flexible material (with a piece ofskidproofing material placed therebetween) for packing frozen food. Inthe real-life situation that is simulated, a first bag is filled withfrozen food and therefore its antislip coated flexible material is kept,by its contents, freezing cold, and before the skidproofing material andthe other filled (and therefore cold) bag is respectively placed on thefirst bag, the first bag spends some 3 minutes time waiting, with itscarrier front surface, and its coating, exposed to the ambient air whichis usually of a temperature of between 0° C. and 4° C., and, for exampleif it is a packaging of frozen fish at sea, the air humidity is, atworst, 100%. The moisture from the air continuously freezes out on thefront surface, and coating, of the bag, and the ice layer it forms isgetting thicker by time. If the roughening projections are suitablyformed, 3 minutes is not enough for the ice to build such thick as wouldkeep a general plane of the skidproofing material, placed onto the icysurface, above the widest parts of the roughening projections of thefirst bag. In case the embodiment follows our teachings generallydescribed herein, it can, for example, be enough that tops of some ofthe roughening projections reach above a top level of the ice, whichresults in an unparalleled resistance of the product to ice buildup. Theice test preparation, as used herein, includes, that in at least thecarrier front surface and the coating of the first specimen a thirdtemperature of between −15° C. and −25° C. is maintained. If thestatic-friction test is fulfilled with selecting −15° C., the feature ispresent. It is reasonable to assume that if the test is fulfilled at anytemperature between −15° C. and −25° C., it would have been fulfilledwith −15° C. also, because the colder the surface is, the faster the icebuildup is (see hereinunder). For example the first specimen can beattached flat onto a flat top of a thick block of ice prepared to be ofa desired temperature. (This is going to be the incline, later.) Thatmaintains the third temperature in the first specimen's upper,roughened, surface during the minutes of the ice test preparation, whichcan readily be checked, for example, with an infrared thermometer. Thefirst specimen, attached to the ice block, must be prepared in a dry,cold place and only exposed to the moist air when the preparation timeis started. The second specimen and the skidproofing material specimencan be kept in a freezer of the third temperature at low air humidity,the second specimen suitably attached to a sled in accordance with thestandard. This way the sled also gets the same cold. The ice testpreparation ends at the moment the preparation time runs out.Immediately thereafter the pre-cooled skidproofing material specimen andthe sled assembly including the second specimen must be respectivelyplaced onto the icy surface of the first specimen (which is stillattached to the block of ice), and the inclined-plane-typestatic-friction test must be performed with a suitable inclining of theice block, together with the whole assembly thereon, otherwise inaccordance with the standard TAPPI T 815. We note that another reasonwhy this test must be performed at the mentioned unusual temperatures isthat the behaviour of the mentioned antislip system, both, of theroughening projections and, mainly, of the skidproofing material,becomes different if they are cooled to such an extent. Namely, polymersused for packaging materials, particularly polyolefins are known to showa definite increase in modulus and tear strength if the temperature istaken from 18° C. to −20° C., and the difference is especially dramaticif their glass transition temperature is between the two points, as isthe case with polypropylene. Advantages of this feature include that theproduct is more resistant to a contamination of ice, as well as finedust, settling on the antislip surface.

It is further preferable, if the method includes providing the antislipcoated flexible material having with the skidproofing material anaverage blocking load less than 200 grams (preferably less than 150grams, more preferably less than 100 grams, more preferably less than 80grams, more preferably less than 60 grams) according to the standardASTM D 3354-96. In the test, specimens must be arranged in a way thatthe skidproofing material specimen is above the antislip coated flexiblematerial specimen, the latter with its coating looking upward. Thisfeature can be provided for by forming the roughening projections havingsuitable geometric features with respect to the skidproofing materialfor preventing substantial mechanical bonds with the filaments of theskidproofing material in a lifting-off operation. Products of aplurality of method embodiments, the products having rougheningprojections, can be suitable for the purpose of the shearing mechanicalinterlock with the skidproofing material, and they can be dimensioned,for example, based on trial and error. In general, such rougheningprojections can have the most suitable geometric features for theshearing interlock as have a shape including an undercut. For example,the mentioned obtuse second contact angle of the roughening projectionswith the front surface can help to establish a mechanical interlock in ashearing direction, though its extent can have to be decreased (forexample by increasing the melt mass flow rate in the second polymer) ifit seems to provide an undesired mechanical interlock also in thelifting operation. The same holds, analogously, for the mentionedroughening projections with substantially flat tops larger than theirfeet, roughening projections with hidden surface portions, androughening projections having at least one undercut. We found that ourmethod embodiments can readily form roughening projections whoseundercut is inherently usually not emphasised enough for providing anessential engagement with the fibrous skidproofing material in thepeeling and lifting directions, which (among others) is believed todistinguish our antislip system, for example, from a typical hook andloop fastening application. The result is that, for example, filledantislip bags or wrapped items, using our present antislip solution, canbe lifted up vertically from each other without extra efforts, andsimilarly, unused bags with a piece of skidproofing material fixed toone of their sides, delivered flat, piled up on pallets, can be liftedup from each other easily.

It is preferable, if the method includes forming the antislip coatedflexible material having at least some of (preferably: at least amajority of) the discrete roughening projections essentially free ofmolecular orientation. It can be provided, for example, by providing thefirst layer essentially without a molecular orientation and preventingthe coating from getting essentially molecularly oriented. Discreteroughening projections being essentially free of molecular orientationcan be recognised, for example, from their behaviour in a test when theyare heated to soften or melt. Namely, such, heated, rougheningprojections will essentially not heat-shrink, and, in general, willessentially possibly not be deformed other than at most in response tosurface energies of the softened or molten substance of the rougheningprojections and the environment. If necessary, the tested rougheningprojections can be detached, for example by a sharp blade, from thecarrier, before the testing. They can be heated for example withimmersing them into hot silicone oil, as is usual with shrinking tests.Alternatively, they can be heated with a heated-air gun. Its advantagesinclude that it can help the coating not to interfere with, particularlynot to distort in one direction, the original heat shrinkingcharacteristics of the carrier, which can be beneficial during a heatshrinking or welding or fusing of the product. Further, such discreteroughening projections can better keep their own desired shapes if theyare exposed to heat, for example during a heat shrinking of the antislipcoated flexible material, which is beneficial, for example, in respectof the antislip quality of heat-shrunk packages made this way.

It is preferable, if the forming of the bond between the carrier and thecoating including the roughening projections includes fusing theroughening projections with the carrier utilising the heat energy of thehot roughening projections. It is possible, for example, that acompatibilising layer is utilised to constitute the front surface of thecarrier so that an enhanced bond may be formed.

It is further preferable, if the forming of the bond includes weldingthe roughening projections to the carrier utilising the heat energy ofthe hot roughening projections.

Advantages include that such bonds are strong and such roughenedproducts can be non-blocking even if stored in a warm storehouse.Further, there is not any need for expensive (for example,tackifier-containing) hot melt adhesives, but cheaper commoditypolymers, possibly even recycled polymers can be used in the rougheningprojections.

It is preferable, if the method includes providing the front surfacewith respective depressions under the feet of at least some of theroughening projections. This can be provided, for example, by impressingthe roughening projection, or it can be formed in any other way, forexample by deforming the front surface under the roughening projection,for example by embossing or local heat shrinking (for example by theheat energy of the hot roughening projection) or in any other way. Thisfeature has particular significance in combination with other mentionedpreferred embodiments, such as with the ratio of the top width to thefoot width being at least 1, and/or with the area of the foot beingsmaller than the area of the top, and/or with the edge angle being atmost 90 degrees, and/or with the side view of the roughening projection(strictly) tapering from the edge to the foot, and/or with theslip-decreasing mechanical interlock in the shearing direction with theskidproofing material and/or with the melt mass flow rate beingrelatively low (which helps to retain the sharp top edge even after aheat shock during a use of the product), namely, these features help thefarthest point, top edge, of the roughening projection perform theantislip interlock despite the fact that the foot of the rougheningprojection stays somewhat deeper, in a depression or indentation. Itsadvantages include that this feature makes this product distinguishablefrom other products; the roughening projection can have a firmer bonddue to being “nested” into the front surface. Further, this feature canbe the sign of the fact that the carrier is relatively intact andstrong, even under the roughening projection (heat-bonded or fused, forexample, welded thereto), namely such a depression can be the result ofthe carrier locally melting and heat-shrinking next to the rougheningprojection because of the heat of the roughening projection but only ina part of its thickness, and for example the back surface of the carriernot melting and not heat-shrinking combined with the front surface ofthe carrier locally melting and heat-shrinking result in thebimetallic-like behaviour in which a local area of the front surfacebecomes smaller than that of the back surface, that causing thedepression. The rear part of the carrier body remaining unmelted canhelp the carrier remain strong.

For the same advantages, it is preferable if a depth of the depressionis formed small enough to keep a widest part of the rougheningprojection above a rest of the front surface in at least one side viewof the roughening projection. As used herein, the widest part is thatsection (generally parallel with the front surface) of the rougheningprojection, whose width is the greatest of all, in the given side view.The rest of the front surface means a part of the front surface, otherthan the depression, around the depression. The term “above” means aboveif the front surface is kept horizontally, looking upward.

It is preferable, if the method includes

-   -   providing respective inter-particle distances between        neighbouring discrete particles of the provided first layer, and    -   providing the hot release surface in a revolving endless belt        having a running direction, and    -   keeping the endless belt alternatingly shifted, perpendicularly        to the running direction, between two lateral end positions,        providing a lateral displacement of the belt between the two        lateral end positions, the lateral displacement being equal to        or greater than an average of the inter-particle distances        (preferably greater than twice the average, more preferably        greater than 3 times the average).

This alternating lateral shifting of the belt has advantages that aresurprising and specific to the current invention features. Advantagesinclude that it helps to avoid bumps formed in the rewound antislipcoated flexible material due to possible respective places of thickerand thinner coating, or even a local lack of coating. A furtheradvantage can be that it helps to statistically hit all possibleparticle-residues, left on the release surface from earlier, with newlysupplied discrete particles in order of picking up the residues from therelease surface, which has a particular significance in order ofpreventing the residues from oxidising or decomposing by time from theexpressly high temperature of the release surface. Namely, (partly)oxidised or decomposed particles can be more difficult to remove fromthe release surface than other ones.

It is preferable, if the method includes forming a packaging bag orpackaging wrap that includes the provided antislip coated flexiblematerial, with at least a part of the coating looking toward an outsideof the bag or wrap. The forming of the bag or wrap can take placebefore, during and/or after the providing of the coating on the carrier.For example, a provided (for example, film or fabric) bag or wrap canconstitute the provided flexible carrier having a front surface. The bagcan preferably be a heavy duty bag, for example for 5 to 90 kg contents,or a medium duty bag, for example for 1 to 5 kg contents. The bag can bea pre-manufactured individual bag provided for a packaging or it can bea bag made on a form-fill-seal machine when the packaging is done. Thewrap can be, for example, collation wrap, shrink wrap, shrink hood,timber wrap, stretch wrap, stretch hood, or any other kind of packagingwrap. The bag can be formed and/or closed with welding, sewing oradhering, or otherwise. The wrap can be fixed around the contents withheat (including shrinking and/or fusing) or taping or stapling orstretching, or otherwise. Both the bag and the wrap can include a filmand/or a woven fabric and/or a nonwoven fabric. Both the bag and thewrap can be heat-shrinkable or can be heat-shrunk onto their contents.Both in the bag and the wrap the carrier can be printed before and/orafter the method performed for forming the antislip flexible material.

In a second aspect, the essence of a product invention is an antislippackaging bag or packaging wrap, formed at least partly from an antislipflexible material including a flexible carrier, the carrier having afront surface with a multiplicity of discrete, solid rougheningprojections

-   -   looking toward an outside of the bag or wrap,    -   the roughening projections including a thermoplastic second        polymer,    -   the roughening projections being essentially free of molecular        orientation,    -   the roughening projections having respective feet, the foot        being an end of the roughening projection attaching to the        carrier,    -   the roughening projections having a second contact angle of        between 90 and 178 degrees (preferably of between 91, more        preferably 92, more preferably 93, more preferably 94, more        preferably 95, more preferably 96, more preferably 97 degrees        and 178 degrees) with the front surface in at least one side        view of the roughening projection,

the bag or wrap being new in that

at least some of the roughening projections, the flat-topped rougheningprojections, have a substantially flat top forming an edge at leastpartially surrounding the substantially flat top.

Definitions and comments as well as objectives and recognition elementsand stated advantages used in the first aspect section in respect ofsuch terms and expressions and features as we use, or whose analogousvariants we use, in this second aspect section are also valid for thissecond aspect section without further mentioning, unless otherwisespecified hereinunder.

The specification allows that the bag or wrap can further includefurther projections other than specified herein. As used herein, theflexible carrier can be a plastic (e.g. thermoplastic film or fabric) ornon-plastic (e.g. kraft paper) carrier or a composite thereof. Asconcerning a distribution of the discrete roughening projections on themacro scale, it is possible that the discrete roughening projections arepresent essentially along the whole front surface of the carrier, but itis also possible that the carrier has one or more places, formingshapes, where the front surface has the roughening projections, on themacro scale. For example the roughening projections can make up one ormore stripes or spots in the outer surface of one or more side panels ofthe bag or wrap on the macro scale. The roughening projection is solid,and has a foot attaching to the carrier and it means that the rougheningprojections are not hollow and include additional material above thecarrier. The definition implies that they are other than pure embossedprojections made (or as if made) with locally pressing the carrier outof its original plane forming on one side a projection and on the otherside a corresponding depression. A foamed second polymer is allowed toconstitute the roughening projections, however second polymers otherthan foamed are preferred. The roughening projection can, in general, bea result of any suitable manufacturing process, it can be made withintegrally moulding together with the carrier, as well as with mixingadded bodies into a material of the carrier during its forming, orfixing (e.g. adhering or fusing or welding etc.) bodies to the frontsurface where the fixed bodies can be pre-shaped and/or they can beshaped during and/or after their fixing etc. Advantages of the productinclude that such discrete, molecularly unoriented rougheningprojections can better keep their own desired shape, and can alsorefrain from distorting the carrier around themselves, when they getexternal heat (for example from a hot filling or from a covering by ashrink wrap) during use, the second contact angle helping to give a formwith an undercut to the roughening projections which makes them moresuitable for an antislip mechanical interlock, in the shearingdirection, with similar roughening projections of a facing surface, orwith a fibrous skidproofing material, while the flat top and the edgealso provide their advantages described in the first aspect section.

It is preferable, if at least a majority of the roughening projectionsare flat-topped roughening projections.

It is preferable, if in at least some of the flat-topped rougheningprojections the substantially flat top forms the edge completelysurrounding the substantially flat top. It is further preferable, if theedge essentially forms a circle.

It is preferable, if in the antislip flexible material, an averagesurface mass of the multiplicity of the discrete roughening projectionsis lower than 1.5 times (preferably lower than 1.25 times, morepreferably lower than 1.00 times, more preferably lower than 0.75 times,even more preferably lower than 0.60 times) an average surface mass ofthe carrier. The average surface mass of the multiplicity of thediscrete roughening projections is the mass of the multiplicity of thediscrete roughening projections divided by the area of the carrier thatis rough with the multiplicity of the discrete roughening projections.Its advantages, in addition to its economy, include that it improves aflexibility of the product.

It is preferable, if the multiplicity of the discrete rougheningprojections are of a random distribution in a top plan view of theantislip flexible material.

It is preferable, if the flat-topped roughening projections are ofrandom top-plan-view sizes.

It is preferable, if the flat-topped roughening projections are ofrandom orientations in a top plan view of the antislip flexiblematerial. As used herein, orientation of a roughening projection in atop plan view does not refer to a molecular orientation of the polymerof the roughening projection but to its angular position.

It is preferable, if in at least one side view of at least someflat-topped roughening projections at least one part, of a contour lineof the roughening projection, connecting the foot and the edge, isconvex from outside.

It is further preferable, if the at least one contour line part isstrictly convex from outside.

It is preferable, if in at least one side view of at least someflat-topped roughening projections a ratio of a width of thesubstantially flat top to a foot width is from 0.50 to 1.24. (Preferablyfrom 0.8 to 1.24, more preferably from 0.9 to 1.24, more preferably from1 to 1.24, more preferably from 1 to 1.20, more preferably from 1 to1.18, more preferably from 1 to 1.15, even more preferably from 1 to1.10.)

It is preferable, if in at least some of the flat-topped rougheningprojections an area of the foot is essentially equal to, or smallerthan, an area of the substantially flat top.

It is further preferable, if the area of the foot is smaller than thearea of the substantially flat top.

It is preferable, if the edge forms an edge angle being an angle,measured through the roughening projection, closed between thesubstantially flat top and a mantle surface extending from the edge tothe foot,

It is further preferable, if at least some of the flat-topped rougheningprojections have the edge angle essentially equal to, or smaller than,90 degrees, in at least one side view of the roughening projection.

It is further preferable, if the edge angle is smaller than 90 degrees,(preferably smaller than 87 degrees, more preferably smaller than 84degrees, more preferably smaller than 81 degrees, more preferablysmaller than 78 degrees). On the other hand, it can be selected to begreater than 30 degrees to provide a suitable strength of the edge.

It is preferable, if at least one side view of at least some flat-toppedroughening projections tapers from the top surface edge to the foot.

It is further preferable, if each side view tapers from the top surfaceedge to the foot.

It is further preferable, if the side view strictly tapers from the topsurface edge to the foot.

It is preferable, if the flat-topped roughening projections project fromtheir respective feet to respective projection heights and haverespective smallest top-plan-view extents and within at least a majorityof the flat-topped roughening projections a coefficient of variation ofthe smallest top-plan-view extents is greater than a coefficient ofvariation of the projection heights. As used herein, a “majority” of theflat-topped roughening projections means a number of the flat-toppedroughening projections greater than half of a total number of theflat-topped roughening projections.

It is further preferable, if the coefficient of variation of thesmallest top-plan-view extents is at least 1.15 times (preferably atleast 1.2 times, more preferably at least 1.3 times, more preferably atleast 1.4 times, more preferably at least 1.5 times, more preferably atleast 1.6 times, more preferably at least 1.7 times, more preferably atleast 1.8 times, more preferably at least 1.9 times, more preferably atleast 2.0 times) the coefficient of variation of the projection heights.

It is further preferable, if in at least some of the flat-toppedroughening projections, a smallest top-plan-view extent of theroughening projection equals at least 1.75 times (preferably at least1.8 times, more preferably at least 1.9 times, more preferably at least2.0 times, more preferably at least 2.1 times) the projection height.

It is preferable, if tops of at least a majority of the flat-toppedroughening projections are essentially in alignment along a planeparallel with a general plane of the front surface.

It is preferable, if at least some of the flat-topped rougheningprojections have a hidden surface portion being a portion of an outersurface of the roughening projection which the roughening projectioncovers from a viewer in a top plan view of the antislip flexiblematerial taken from above the roughening projections.

It is further preferable, if the at least some of the flat-toppedroughening projections have at least one undercut and include at leastone area immediately above the undercut, the roughening projection beingso dimensioned as to form a separation between the at least one area andthe front surface which is greater than 10 micrometres (preferablygreater than 12 micrometres, more preferably greater than 15micrometres, more preferably greater than 20 micrometres).

It is preferable, if the second polymer has a melt mass flow rate of 0.1to 300 g/10 min (preferably 0.1 to 250 g/10 min, more preferably 0.1 to200 g/10 min, more preferably 0.1 to 150 g/10 min, more preferably 0.1to 100 g/10 min, more preferably 0.1 to 80 g/10 min, more preferably 0.1to 60 g/10 min, more preferably 0.1 to 40 g/10 min, more preferably 0.1to 30 g/10 min, more preferably 0.1 to 20 g/10 min, more preferably 0.1to 10 g/10 min) determined at 190° C. under a load of 2.16 kg inaccordance with ISO 1133-1. Advantages include that the lower the meltmass flow rate of the second polymer, the better the rougheningprojections will keep their original forms (against a spontaneousbead-forming) when they get external heat, for example during a fusingor welding of the product or in a heat shrinking of the product, or whenhot contents are filled into the bag made from the product. Further, themelt mass flow rate being greater than 0.1 g/10 min can help to providean easy sealability, weldability of the product, namely when theroughening projections happen to be between sealing or welding toolsduring a sealing or welding then they can become pliably compressibleenough not to remain “spacers” keeping the welding tools from abutting.This feature can further improve with selecting even higher melt massflow rate values in the lower limit of the value range (for example 0.5or 1.0 or 1.5 or even 2.0 g/10 min).

It is preferable, if the carrier at least partly includes athermoplastic first polymer. Here the roughening projections beingessentially free of molecular orientation receives an even greatersignificance because an antislip flexible material with a thermoplasticcarrier can also receive external heat for other reasons, like closing,forming or shrinking the bag or wrap itself, with heat, e.g. withheat-blowing, fusing, welding etc. Also, a common recyclability of thecarrier and the roughening projections arise. A heat shrinkable carriergives a concrete significance to the beneficial behaviour of theroughening projections during a heat shrinking of the carrier. It isfurther preferable, if the thermoplastic first polymer of the carrier isweldable and/or fusable for one or both of a forming and a closing ofthe bag or wrap. It is further preferable, if the carrier at leastpartly includes a heat shrinkable layer including the thermoplasticfirst polymer. It is further preferable, if the heat shrinkable layerhas a heat shrinkability of at least 5% (preferably at least 10%, morepreferably at least 15%, more preferably at least 20%). It means thatthe heat shrinkable layer has the mentioned heat shrinkability in atleast one direction. It is further preferable, if the first polymer andthe second polymer are compatible in recycling. This is advantageousbecause it also helps in fusing or welding the antislip flexiblematerial with itself with the roughening projections getting betweenfacing antislip flexible material pieces.

It is further preferable, if one or both of a melting temperature and asoftening temperature of the first polymer are either lower than orequal to or at most 50° C. degrees higher than a softening temperatureof the second polymer. Its advantages include that thereby the softeningtemperature of the roughening projections can not be very much lowerthan that of he carrier, which helps to avoid a situation in which aheat used to, for example, fuse or shrink or weld the carrier proves tobe excessive for the roughening projections causing an extremely lowviscosity in the roughening projections that would possibly lead to theroughening projections losing their desired shape to an undesiredextent.

It is further preferable, if an average surface mass of the carrier isless than 500 g/m² (preferably less than 420 g/m², more preferably lessthan 370, or 320, 270, 220, 200, 180, 160, 140, 130, or even 120 g/m²).Advantages of a carrier of a relatively low surface mass include that itneeds less heat for its shrinking, fusing, welding etc., and it helps toprevent the roughening projections from being spoiled from the heat.

It is preferable, if at least a majority of the flat-topped rougheningprojections have a top-plan-view size of at least 30 micrometres and atmost 40 millimetres (preferably of at least 40 micrometres and at most20 millimetres).

It is preferable, if the multiplicity of the roughening projections havean average top-plan-view aspect ratio of at least 1.0 and at most 20.0(preferably at most 19.0, more preferably at most 18.0, more preferablyat most 17.0, more preferably at most 16.0, more preferably at most15.0, more preferably at most 14.0, more preferably at most 13.0, morepreferably at most 12.0, more preferably at most 11.0, more preferablyat most 10.0, more preferably at most 9.0, more preferably at most 8.0,more preferably at most 7.0, more preferably at most 6.0, morepreferably at most 5.0, more preferably at most 4.0, more preferably atmost 3.0, more preferably at most 2.0, even more preferably at most1.75). Its advantages include that a lower average top-plan-view aspectratio value provides, in the antislip flexible material, a greaterflexibility with a greater isotropy of the flexibility, and (ifheat-shrinkable) a greater heat-shrinkability with a greater isotropy ofthe heat-shrinkability.

It is preferable, if the roughening projections are fixed to thecarrier. Its advantages include that it allows a simple and economicalway of making.

It is further preferable, if the roughening projections are formed ofparticles fixed to the carrier.

It is further preferable, if the roughening projections are fixed to thecarrier without an essential penetration into the carrier. As usedherein, an intermolecular diffusion between the roughening projectionsand the carrier is not considered to be a penetration into the carrier.

It is further preferable, if the bag or wrap includes a heat bondbetween the carrier and the roughening projections. Advantages includethat the bond is strong and clean and economical to make.

It is further preferable, if the bag or wrap includes a fused bondbetween the carrier and the roughening projections.

It is further preferable, if the bag or wrap includes a welded bondbetween the carrier and the roughening projections. Advantages includethat it can provide very strong bonds economically.

It is preferable, if the carrier includes a fabric woven from plastictapes, and the antislip flexible material has at least some rougheningprojections heat-bonded to the fabric at such places where the fabrichas the tapes forming with each other respective overlaps, the fabricbeing free of a fused bond between the tapes in the overlaps.

It is preferable, if the carrier includes a fabric woven from plastictapes, the tapes exposed at least in a part of a surface of the carrier,and at least one (preferably: at least some) flat-topped rougheningprojection has suitable geometric features with respect to the exposedtapes for forming with at least one of the exposed tapes aslip-decreasing mechanical interlock.

It is preferable, if the antislip flexible material is capable of aslip-decreasing mechanical interlock in a shearing direction with askidproofing material, of an ordinary polypropylene spunbonded nonwovenfabric of an average surface mass of 17 g/m² and filament thickness ofbetween 25 and 30 micrometres, due to the roughening projections havingsuitable closeness and geometric features with respect to theskidproofing material for forming mechanical bonds with the filaments ofthe skidproofing material in the shearing direction.

It is further preferable, if a static friction between two specimens ofthe antislip flexible material, with a specimen of the skidproofingmaterial placed between the specimens of the antislip flexible material,is suitably high to resist sliding in an inclined-plane-typestatic-friction test of 50 degrees angle (preferably of 55 degreesangle, more preferably of 60 degrees angle, more preferably of 65degrees angle) according to the TAPPI T 815 standard.

It is further preferable, if the static friction is suitably high toresist the sliding immediately after a preparation, the ice testpreparation, the ice test preparation including maintaining in at leastthe carrier front surface, and the roughening projections, of a firstone of the two specimens of the antislip flexible material a thirdtemperature of between −15° C. and −25° C. while exposing the carrierfront surface and the roughening projections to air of a temperature ofbetween 0° C. and 4° C. and of a relative humidity of 100% for apreparation time of 3 minutes (preferably of 5 minutes, more preferablyof 8 minutes) and the ice test preparation further including providing asecond one of the two specimens of the antislip flexible material andthe specimen of the skidproofing material of the third temperature.

It is further preferable, if the antislip flexible material has with theskidproofing material an average blocking load less than 200 grams(preferably less than 150 grams, more preferably less than 100 grams,more preferably less than 80 grams, more preferably less than 60 grams)according to the standard ASTM D 3354-96.

It is further preferable, if the skidproofing material, or an otherfibrous engaging element with which the antislip flexible material iscapable of the slip-decreasing mechanical interlock in the shearingdirection, is fixed to the outside of the bag or wrap. The other fibrousengaging element can be any suitable such element, for example(preferably textured) fibre or yarn sections and/or fibre or yarn loopsand/or fibres or yarns and/or a net of fibres or yarns suitably fixed tothe outside or for example a nonwoven that differs in one or more of itssubstance, surface mass, filament thickness and production method fromthe skidproofing material. For example it can be polyethylene orpolyester spunlaced nonwoven fabric of an average surface mass of 12 or22 g/m² and filament thickness of between 18 and 24 micrometres. Theimportant thing is that the other fibrous engaging element comprisesfibres of such closeness and layer thickness that between the fibres ofthe other fibrous engaging element and the roughening projections amechanical joint can be formed and the antislip flexible material iscapable of the slip-decreasing mechanical interlock in the shearingdirection with the other fibrous engaging element, due to the rougheningprojections having suitable closeness and geometric features withrespect to the other fibrous engaging element for forming mechanicalbonds with the filaments thereof in the shearing direction. The fixingcan include a fixing against lifting and peeling and a fixing againstslipping, which all can be provided with any suitable means for examplewith adhering, sticking, taping, welding, fusing, sewing, extrusionlaminating etc. Fixing against slipping can further be provided for byproviding roughening projections adjacently to the skidproofingmaterial, or the other fibrous engaging element respectively, covered upby the latter.

It is preferable, if the antislip flexible material has with itself anaverage blocking load less than 200 grams (preferably less than 150grams, more preferably less than 100 grams, more preferably less than 80grams, more preferably less than 60 grams, more preferably less than 50grams, more preferably less than 40 grams, more preferably less than 30grams) in a modified blocking load test.

It is preferable, if at least a majority of the roughening projectionsare essentially free of a tackifier.

It is preferable, if the multiplicity of the roughening projectionsoccupy at most 75% (more preferably at most 60%, or 50% or 40%, or 35%,or 30%, or 25%, or 20%, or 17.5%, or 15.0%, or 12.5%, or 10.0%, or evenmore preferably at most 8.0%) of an area of the antislip flexiblematerial in a top plan view. This is meant on the micro scale, whereininterstices between the roughening projections, where the front surfaceis exposed, are not considered to be occupied.

It is preferable, if the front surface has respective depressions underthe feet of at least some of the flat-topped roughening projections.

It is further preferable, if a depth of the depression is small enoughto keep a widest part of the roughening projection above a rest of thefront surface in at least one side view of the roughening projection.

In a third aspect, the essence of a method invention is a method forproducing an antislip packaging bag or packaging wrap, the bag or wrapaccording to the second aspect of the invention, including

-   -   forming a packaging bag or packaging wrap at least partly from        an antislip flexible material including a flexible carrier,    -   providing a front surface of the carrier,    -   providing in the antislip flexible material a multiplicity of        discrete, solid roughening projections projecting from the front        surface and looking toward an outside of the bag or wrap,    -   providing a thermoplastic second polymer included in the        roughening projections,    -   providing the roughening projections essentially free of        molecular orientation,    -   providing the roughening projections with respective feet, the        foot being an end of the roughening projection attaching to the        carrier,    -   providing the roughening projections with a second contact angle        of between 90 and 178 degrees formed with the front surface in        at least one side view of the roughening projection,

the method being new in

providing at least some of the roughening projections, the flat-toppedroughening projections, with a substantially flat top forming an edge atleast partially surrounding the substantially flat top.

Definitions and comments as well as objectives and recognition elementsand stated advantages used in the first and/or second aspect sections inrespect of such terms and expressions and features as we use, or whoseanalogous variants we use, in this third aspect section are also validfor this third aspect section without further mentioning, unlessotherwise specified hereinunder.

The specification allows that the bag or wrap can be formed to be inaccordance with any specification allowed in the second-aspect sectionabove. The provided roughening projection is solid, and is provided witha foot attaching to the carrier and it means that the mentionedroughening projections are not hollow and include additional materialabove the carrier. The definition implies that they are formed otherthan purely by embossing, i.e., locally pressing the carrier out of itsoriginal plane forming on one side a projection and on the other side acorresponding depression. The roughening projections can, in general, beprovided or formed with any suitable manufacturing process, they can bemade with integrally moulding together with the carrier as well as withmixing added bodies into a material of the carrier during its forming,or fixing (e.g. adhering or fusing or welding etc.) pre-shaped bodies tothe front surface etc. It is possible that a flat-topped rougheningprojection is formed immediately but it is also possible, for example,that first a roughening projection other than flat-topped is formedprojecting from the front surface (for example with fixing roughlyspherical powder granules to the front surface) and successively it istransformed into a flat-topped roughening projection (for example bycontacting its top region with a flat hot release surface while keepingits foot region cold enough for keeping it from melting). The providingof the roughening projections in the antislip flexible material can takeplace before, and/or during, and/or after the forming of the packagingbag or packaging wrap from the antislip flexible material.

Advantages of the method include that the method is specially adaptedfor the manufacture of the packaging bag or packaging wrap described inthe second aspect section.

Some of the preferred embodiments of the method are analogous withrespective particular preferred embodiments of the second-aspectinvention mentioned above, based on producing the respective particularpreferred embodiments of the second-aspect antislip packaging bags orpackaging wraps.

Preferably, the method includes providing at least a majority of theroughening projections as flat-topped roughening projections.

Preferably, the method includes providing in at least some of theflat-topped roughening projections the substantially flat top formingthe edge completely surrounding the substantially flat top.

Preferably, the method includes providing the edge essentially forming acircle.

Preferably, the method includes providing in the antislip flexiblematerial an average surface mass of the multiplicity of the discreteroughening projections that is lower than 1.5 times (preferably lowerthan 1.25 times, more preferably lower than 1.00 times, more preferablylower than 0.75 times, even more preferably lower than 0.60 times) anaverage surface mass of the carrier.

Preferably, the method includes providing the multiplicity of thediscrete roughening projections with a random distribution in a top planview of the antislip flexible material.

Preferably, the method includes providing the flat-topped rougheningprojections with random top-plan-view sizes.

Preferably, the method includes providing the flat-topped rougheningprojections with random orientations in a top plan view of the antislipflexible material.

Preferably, the method includes providing in at least one side view ofat least some flat-topped roughening projections at least one part, of acontour line of the roughening projection, connecting the foot and theedge, that is convex from outside.

Preferably, the method includes providing the at least one contour linepart strictly convex from outside.

Preferably, the method includes providing in at least one side view ofat least some flat-topped roughening projections a ratio of a width ofthe substantially flat top to a foot width between 0.50 and 1.24.(Preferably from 0.8 to 1.24, more preferably from 0.9 to 1.24, morepreferably from 1 to 1.24, more preferably from 1 to 1.20, morepreferably from 1 to 1.18, more preferably from 1 to 1.15, even morepreferably from 1 to 1.10.)

Preferably, the method includes providing in at least some of theflat-topped roughening projections an area of the foot that isessentially equal to, or smaller than, an area of the substantially flattop.

Preferably, the method includes providing the area of the foot smallerthan the area of the substantially flat top.

Preferably, the method includes providing an edge angle, formed by theedge and being an angle, measured through the roughening projection,closed between the substantially flat top and a mantle surface extendingfrom the edge to the foot.

Preferably, the method includes providing at least some of theflat-topped roughening projections with the edge angle essentially equalto, or smaller than, 90 degrees, in at least one side view of theroughening projection.

Preferably, the method includes the edge angle being smaller than 90degrees (preferably smaller than 87 degrees, more preferably smallerthan 84 degrees, more preferably smaller than 81 degrees, morepreferably smaller than 78 degrees). On the other hand, it can beselected to be greater than 30 degrees to provide a suitable strength ofthe edge.

Preferably, the method includes providing at least one side view of atleast some flat-topped roughening projections tapering from the topsurface edge to the foot.

Preferably, the method includes providing each side view tapering fromthe top surface edge to the foot.

Preferably, the method includes providing the side view strictlytapering from the top surface edge to the foot.

Preferably, the method includes providing the flat-topped rougheningprojections projecting from their respective feet to respectiveprojection heights and having respective smallest top-plan-view extentsand providing within at least a majority of the flat-topped rougheningprojections a coefficient of variation of the smallest top-plan-viewextents greater than a coefficient of variation of the projectionheights.

Preferably, the method includes providing the coefficient of variationof the smallest top-plan-view extents at least 1.15 times (preferably atleast 1.2 times, more preferably at least 1.3 times, more preferably atleast 1.4 times, more preferably at least 1.5 times, more preferably atleast 1.6 times, more preferably at least 1.7 times, more preferably atleast 1.8 times, more preferably at least 1.9 times, more preferably atleast 2.0 times) the coefficient of variation of the projection heights.

Preferably, the method includes providing, in at least some of theflat-topped roughening projections, a smallest top-plan-view extent ofthe roughening projection equalling at least 1.75 times (preferably atleast 1.8 times, more preferably at least 1.9 times, more preferably atleast 2.0 times, more preferably at least 2.1 times) the projectionheight.

Preferably, the method includes providing tops of at least a majority ofthe flat-topped roughening projections essentially in alignment along aplane parallel with a general plane of the front surface.

Preferably, the method includes providing at least some of theflat-topped roughening projections with a hidden surface portion being aportion of an outer surface of the roughening projection which theroughening projection covers from a viewer in a top plan view of theantislip flexible material taken from above the roughening projections.

Preferably, the method includes providing the at least some of theflat-topped roughening projections with at least one undercut and withat least one area immediately above the undercut, providing theroughening projection so dimensioned as to form a separation between theat least one area and the front surface which is greater than 10micrometres (preferably greater than 12 micrometres, more preferablygreater than 15 micrometres, more preferably greater than 20micrometres).

Preferably, the method includes providing the second polymer with a meltmass flow rate of 0.1 to 300 g/10 min (preferably 0.1 to 250 g/10 min,more preferably 0.1 to 200 g/10 min, more preferably 0.1 to 150 g/10min, more preferably 0.1 to 100 g/10 min, more preferably 0.1 to 80 g/10min, more preferably 0.1 to 60 g/10 min, more preferably 0.1 to 40 g/10min, more preferably 0.1 to 30 g/10 min, more preferably 0.1 to 20 g/10min, more preferably 0.1 to 10 g/10 min) determined at 190° C. under aload of 2.16 kg in accordance with ISO 1133-1. Aforementioned advantagescould be provided with selecting even higher melt mass flow rate valuesin the lower limit of the value range (for example 0.5 or 1.0 or 1.5 oreven 2.0 g/10 min).

Preferably, the method includes providing the carrier at least partlyincluding a thermoplastic first polymer.

Preferably, the method includes the thermoplastic first polymer of thecarrier being suitable to be welded or fused for one or both of aforming and a closing of the bag or wrap.

Preferably, the method includes providing the carrier at least partlyincluding a heat shrinkable layer including the thermoplastic firstpolymer.

Preferably, the method includes providing in the heat shrinkable layer aheat shrinkability of at least 5% (preferably at least 10%, morepreferably at least 15%, more preferably at least 20%).

Preferably, the method includes the first polymer and the second polymerbeing compatible in recycling.

Preferably, the method includes providing one or both of a meltingtemperature and a softening temperature of the first polymer eitherlower than or equal to or at most 50° C. degrees higher than a softeningtemperature of the second polymer.

Preferably, the method includes providing an average surface mass of thecarrier less than 500 g/m² (preferably less than 420 g/m², morepreferably less than 370, or 320, 270, 220, 200, 180, 160, 140, 130, oreven 120 g/m²).

Preferably, the method includes providing at least a majority of theflat-topped roughening projections with a top-plan-view size of at least30 micrometres and at most 40 millimetres (preferably of at least 40micrometres and at most 20 millimetres).

Preferably, the method includes providing in the multiplicity of theroughening projections an average top-plan-view aspect ratio of at least1.0 and at most 20.0 (preferably at most 19.0, more preferably at most18.0, more preferably at most 17.0, more preferably at most 16.0, morepreferably at most 15.0, more preferably at most 14.0, more preferablyat most 13.0, more preferably at most 12.0, more preferably at most11.0, more preferably at most 10.0, more preferably at most 9.0, morepreferably at most 8.0, more preferably at most 7.0, more preferably atmost 6.0, more preferably at most 5.0, more preferably at most 4.0, morepreferably at most 3.0, more preferably at most 2.0, even morepreferably at most 1.75).

Preferably, the method includes providing the roughening projectionsfixed to the carrier.

Preferably, the method includes providing the roughening projectionsformed of particles fixed to the carrier. For example, pre-shaped cupshaped solid particles can be adhered to the front surface with alacquer that can be crosslinked with ultraviolet irradiation.

Preferably, the method includes providing the roughening projectionsfixed to the carrier without an essential penetration into the carrier.

Preferably, the method includes providing a heat bond between thecarrier and the roughening projections. For example, a paper carrier canbe provided with roughening projections made of a second polymer that isotherwise suitable for use in an extrusion coating operation for coatingthe paper (for example a copolymer including acrylic acid).

Preferably, the method includes providing a fused bond between thecarrier and the roughening projections.

Preferably, the method includes providing a welded bond between thecarrier and the roughening projections.

Preferably, the method includes providing the carrier including a fabricwoven from plastic tapes, and providing the antislip flexible materialwith at least some roughening projections heat-bonded to the fabric atsuch places where the fabric has the tapes forming with each otherrespective overlaps, keeping the fabric free of a fused bond between thetapes in the overlaps.

Preferably, the method includes providing the carrier including a fabricwoven from plastic tapes, the tapes exposed at least in a part of asurface of the carrier, and providing at least one (preferably: at leastsome) flat-topped roughening projection with suitable geometric featureswith respect to the exposed tapes for forming with at least one of theexposed tapes a slip-decreasing mechanical interlock.

Preferably, the method includes providing the antislip flexible materialcapable of a slip-decreasing mechanical interlock in a shearingdirection with a skidproofing material, of an ordinary polypropylenespunbonded nonwoven fabric of an average surface mass of 17 g/m² andfilament thickness of between 25 and 30 micrometres, due to theroughening projections being provided with suitable closeness andgeometric features with respect to the skidproofing material for formingmechanical bonds with the filaments of the skidproofing material in theshearing direction.

Preferably, the method includes providing a static friction between twospecimens of the antislip flexible material, with a specimen of theskidproofing material placed between the specimens of the antislipflexible material, suitably high to resist sliding in aninclined-plane-type static-friction test of 50 degrees angle (preferablyof 55 degrees angle, more preferably of 60 degrees angle, morepreferably of 65 degrees angle) according to the TAPPI T 815 standard.

Preferably, the method includes providing the static friction suitablyhigh to resist the sliding immediately after a preparation, the ice testpreparation, the ice test preparation including maintaining in at leastthe carrier front surface, and the roughening projections, of a firstone of the two specimens of the antislip flexible material a thirdtemperature of between −15° C. and −25° C. while exposing the carrierfront surface and the roughening projections to air of a temperature ofbetween 0° C. and 4° C. and of a relative humidity of 100% for apreparation time of 3 minutes (preferably of 5 minutes, more preferablyof 8 minutes) and the ice test preparation further including providing asecond one of the two specimens of the antislip flexible material andthe specimen of the skidproofing material of the third temperature.

Preferably, the method includes providing the antislip flexible materialhaving with the skidproofing material an average blocking load less than200 grams (preferably less than 150 grams, more preferably less than 100grams, more preferably less than 80 grams, more preferably less than 60grams) according to the standard ASTM D 3354-96.

Preferably, the method includes providing the skidproofing material, oran other fibrous engaging element with which the antislip flexiblematerial is capable of the slip-decreasing mechanical interlock in theshearing direction, fixed to the outside of the bag or wrap.

Preferably, the method includes providing the antislip flexible materialhaving with itself an average blocking load less than 200 grams(preferably less than 150 grams, more preferably less than 100 grams,more preferably less than 80 grams, more preferably less than 60 grams,more preferably less than 50 grams, more preferably less than 40 grams,more preferably less than 30 grams) in a modified blocking load test.

Preferably, the method includes providing at least a majority of theroughening projections essentially free of a tackifier.

Preferably, the method includes providing the multiplicity of theroughening projections occupying at most 75% (more preferably at most60%, or 50% or 40%, or 35%, or 30%, or 25%, or 20%, or 17.5%, or 15.0%,or 12.5%, or 10.0%, or even more preferably at most 8.0%) of an area ofthe antislip flexible material in a top plan view. This is meant on themicro scale, wherein interstices between the roughening projections,where the front surface is exposed, are not considered to be occupied.

Preferably, the method includes providing in the front surfacerespective depressions under the feet of at least some of theflat-topped roughening projections.

Preferably, the method includes providing a depth of the depressionsmall enough to keep a widest part of the roughening projection above arest of the front surface in at least one side view of the rougheningprojection.

In a fourth aspect, the essence of a method invention is a packagingmethod using an antislip packaging bag or packaging wrap, the methodincluding providing contents, and providing at least one antislippackaging bag or packaging wrap, and packing the contents with the atleast one antislip packaging bag or packaging wrap, for forming at leastone package,

the method being new in

providing the at least one antislip packaging bag or packaging wrapaccording to the second aspect of the invention, including any of itspreferred embodiments.

Definitions and comments as well as objectives and recognition elementsand stated advantages used in the first and/or second and/or thirdaspect sections in respect of such terms and expressions and features aswe use, or whose analogous variants we use, in this fourth aspectsection are also valid for this fourth aspect section without furthermentioning, unless otherwise specified hereinunder.

The product which is made directly by the method, i.e., the at least onepackage, can be, for example one or more packages packed with theantislip packaging bags or packaging wraps or, for example, one or morestacks of such packages, piled up, for example, on one or more palletsand/or on a floor and/or in a vehicle and/or in a vessel, optionallyincluding suitable stack covers, for example, stretch hoods or stretchwraps or shrink hoods or shrink wraps as well. The bag or wrap can beformed before (e.g., individual-bag-packaging, form-fill-seal bagpackaging), or during and/or after (e.g., timber wrapping,stretch-hooding, stretch-wrapping, shrink-hooding) the packing. Thesuitable contents can mean any contents suitable to be packed with theprovided antislip packaging bag or packaging wrap, for example, havingsuitable size, shape, quantity, weight etc. for the purpose. The mostcritical products that may need antislip packaging bags include, forexample, frozen food, fine dusty products like cement and flour, easilyflowing hard granules like quartz sand and blast abrasives, lightweightpowders like perlite and fly ash, and further products like rice, seeds,food- and feed ingredients, hazardous goods etc. The most criticalproducts that may need antislip packaging wraps include timber, drinkcans, and any applications in which flexible collating wraps can be usedfor collating instead of traditionally used carton boxes (for examplehygiene products etc.).

Advantages of the method origin from the advantages of the packagingmaterial used.

Preferably, in the method, the contents include any one or both of a.) aproduct of powder form containing particles of a size which is smallerthan 250 micrometres (preferably smaller than 200 micrometres, morepreferably smaller than 150 micrometres, more preferably smaller than100 micrometres, more preferably smaller than 75 micrometres, morepreferably smaller than 50 micrometres) and b.) frozen food. The productof powder form at least partly consists of particles smaller than thementioned size and it can further suitably include other particles oranything else. The significance of the feature is based on the fact thatat packing up such products the fine dust content can get airborne andsettle on the packages, possibly filling up the front surface around theroughening projections. The same is the situation with the white frostpossibly settling on the frozen food packages.

Preferably, the method includes providing the at least one antislippackaging bag or packaging wrap according to any of the bag or wrapproduct embodiments, of the second aspect, including the bag or wrap,

-   -   wherein in at least some of the flat-topped roughening        projections an area of the foot is essentially equal to, or        smaller than, an area of the substantially flat top, especially        where the area of the foot is smaller than the area of the        substantially flat top, and/or    -   wherein at least some of the flat-topped roughening projections        have the edge angle essentially equal to, or smaller than, 90        degrees, in at least one side view of the roughening projection,        especially where the edge angle is smaller than 90 degrees,        and/or    -   wherein at least one side view of at least some flat-topped        roughening projections tapers from the top surface edge to the        foot, especially where each side view tapers from the top        surface edge to the foot and/or where the side view strictly        tapers from the top surface edge to the foot, and/or    -   wherein the at least some of the flat-topped roughening        projections have at least one undercut and include at least one        area immediately above the undercut, the roughening projection        being so dimensioned as to form a separation between the at        least one area and the front surface which is greater than 10        micrometres, and/or    -   wherein the antislip flexible material is capable of a        slip-decreasing mechanical interlock in a shearing direction        with a skidproofing material, of an ordinary polypropylene        spunbonded nonwoven fabric of an average surface mass of 17 g/m²        and filament thickness of between 25 and 30 micrometres, due to        the roughening projections having suitable closeness and        geometric features with respect to the skidproofing material for        forming mechanical bonds with the filaments of the skidproofing        material in the shearing direction, especially where a static        friction between two specimens of the antislip flexible        material, with a specimen of the skidproofing material placed        between the specimens of the antislip flexible material, is        suitably high to resist sliding in an inclined-plane-type        static-friction test of 50 degrees angle according to the TAPPI        T 815 standard, and particularly where the static friction is        suitably high to resist the sliding immediately after a        preparation, the ice test preparation, the ice test preparation        including maintaining in at least the carrier front surface, and        the roughening projections, of a first one of the two specimens        of the antislip flexible material a third temperature of between        −15° C. and −25° C. while exposing the carrier front surface and        the roughening projections to air of a temperature of between        0° C. and 4° C. and of a relative humidity of 100% for a        preparation time of 3 minutes and the ice test preparation        further including providing a second one of the two specimens of        the antislip flexible material and the specimen of the        skidproofing material of the third temperature, and/or        especially where the antislip flexible material has with the        skidproofing material an average blocking load less than 200        grams according to the standard ASTM D 3354-96, and/or        especially where the skidproofing material, or an other fibrous        engaging element with which the antislip flexible material is        capable of the slip-decreasing mechanical interlock in the        shearing direction, is fixed to the outside of the bag or wrap.

The advantage of the combinations comes from the mentioned bag or wrapproduct features being especially advantageous if used under icy ordusty circumstances.

Preferably, in the method, the contents include frozen food.

More preferably, in the method, the packing takes place aboard a vessel.

This combination gives a special significance to the invention becausethe storage room in a vessel (for example, a fishing vessel at sea) canbe tilted by the waves creating a strong need for a good antislippackaging while the frozen food contents in combination with the usuallyhigh air relative humidity, aboard vessels, involve the factor of frostprecipitating on the bags, as mentioned earlier.

More preferably, the method includes

-   -   providing blocks of plate-frozen seafood as the contents, and    -   providing at least two, first and second, of the antislip        packaging bags according to the product embodiment, of the        second aspect, wherein the skidproofing material, or an other        fibrous engaging element with which the antislip flexible        material is capable of the slip-decreasing mechanical interlock        in the shearing direction, is fixed to the outside of the bag or        wrap, and    -   packing the blocks into the bags for forming a first package        including the first bag and one or more blocks packed therein        and a second package including the second bag and one or more        blocks packed therein,    -   the first and second packages being suitable to pass a stack        tilting test without sliding on each other during the stack        tilting test,    -   wherein the stack tilting test includes        -   providing a horizontal stacking base,        -   forming a stack from the first and second packages including            -   laying the first package on the horizontal stacking base                and        -   at least partly placing the second package upon the first            package, with their centres of mass above each other, and            with the skidproofing material, or the other fibrous            engaging element with which the antislip flexible material            is capable of the slip-decreasing mechanical interlock in            the shearing direction, fixed to the outside of the first            bag providing the slip-decreasing mechanical interlock in            the shearing direction with the antislip flexible material            of the second bag, and        -   tilting the stacking base into a slanting orientation            closing with the horizontal an angle of 35 degrees            (preferably an angle of 45 degrees), and        -   immediately thereafter turning the stacking base back to            horizontal.

As used herein, seafood includes fish and other seafood caught, forexample, at sea. Plate freezing is known to be one of the fastestfreezing methods, useful for freezing the catch on board of a fishingboat as fast as possible. As it is known, a plate-frozen block ofseafood has a characteristic flat shape, its flat top and bottomsurfaces defined by the planar and parallel freezing plates betweenwhich the seafood was kept compressed while frozen. Such flat-shapedfrozen blocks, of a typical height of about 10 cm, can be readilystacked upon each other with an essentially horizontal orientation ofthe blocks. During the packing, into each bag one or more blocks can beplaced, and the bag is preferably suitably closed, for example by sewingand/or taping and/or fusing. The provided bags are suitable (i.e., areantislip enough) to result such packages as are suitable to pass a stacktilting test without sliding on each other during the stack tiltingtest. As used herein, sliding means starting to slide and sliding untila hit. We note that the packages are considered to be suitable to pass astack tilting test without sliding on each other, for example, if thesecond package starts to slide on the first package and thereafter itfinally stops purely due to shear forces acting between the packages. Asit is defined above, the stack tilting test virtually includes puttingthe two packages on top of each other, with their mating antislipsurfaces in a suitable engagement against slipping and exposing theassembly to a temporary 35-degree tilting, which simulates an effect ofsea waves on the storage room in a vessel. In the stack tilting test,the second package is placed upon the first package with their centresof mass above each other, which means that their respective centres ofmass define a vertical line. In further respects of the stack tiltingtest we refer to the standard TAPPI T 815. A suitable selection can beachieved, by the skilled person, for example by trial end error. Forexample, if the selected packages do not pass the stack tilting testthen one could decrease a filling weight in the bags, or improve theantislip performance of the bags as taught in the second aspect section.For example, a larger piece of the skidproofing material, or of theother fibrous engaging element, could be applied and/or a larger surfacepart of the bags could be provided with the roughening projections onthe macro scale and/or a closeness and/or geometry of the rougheningprojections could be changed in order of a stronger slip-decreasingmechanical interlock in the shearing direction.

More preferably, in the method, the first and second packages aresuitable to pass two successively performed stack tilting tests withoutsliding on each other during any one of the stack tilting tests whereimmediately between the stack tilting tests the second package is pulledwith a horizontal speed off the first package.

This feature expresses that the packages do not lose too much of theirmutual antislip performance even if the second package is dragged, withan at least partly horizontal pulling force, on the flat top of thefirst package until it is pulled off from the first package. For thepulling off, one tilts the top package to stand it onto its edgeotherwise it could be too difficult or impossible to slide it. To makebags suitable for such packages, the skilled person should provide asufficient number of roughening projections in the surface of the secondbag as well as a sufficient strength of the roughening projectionsagainst breaking off or getting deformed, in order to provide a suitablenumber of roughening projections surviving that the second package ispulled off the first package. The skilled person should follow theprinciple that it is better to break the filaments of the skidproofingmaterial, or of the other fibrous engaging element, than to break theroughening projections, during the pulling-off. Namely, the skidproofingmaterial or the other fibrous engaging element, in practice, can havemuch more free filaments available for engagement with rougheningprojections than the number of roughening projections, in the secondbag, available for forming the mechanical bonds with the filaments.Therefore, the number of possible “roughening-projection—filament”elementary engagements is virtually limited by the number of availableroughening projections. Therefore, if some or many of the filamentsbreak during the pulling-off there is not a big problem as long asmany-enough of the roughening projections remain useful.

The advantages of providing such packages include that such packages canbetter meet the needs arising on a fishing vessel. Namely, a stack ofblock frozen packages typically gets manually re-stacked at least oncebecause of the special logistics in the fishing industry, and since thepackages are hard and block-shaped (unlike, for example, bag packages ofindividually quick frozen green peas), they can not be rolled off eachother but they must be either lifted up, vertically, or pulled off,horizontally, from each other. That is what involves the mentionedpulling-off operation.

Further, preferably, the method includes at least partly heat shrinkingthe packaging bag or packaging wrap around the contents. This can happenwith a heat blowing gun and/or in a heating tunnel and/or with any othersuitable means. The bag or wrap, as we mentioned, can, for example, beof a film or a fabric. The term at least partly, as used herein, meansthat one or more parts of the packaging bag or packaging wrap can beleft un-shrunk and further, one or more parts of the packaging bag orpackaging wrap can be heat shrunk less than would be possible based on aheat shrinking capability of the packaging bag or packaging wrap.

Further, preferably, the method includes a stacking of the at least onepackage. The stacking can include piling up the packages on a floor orground and/or in a vehicle and/or in a vessel and/or on one or morepallets or similar means of storage and transport. The stacking caninclude applying the stacks in plural layers of stacks, for example withputting a stack on top of other stack(s). The stacking is preferablyconfigured in a way suitable to exploit antislip features provided inthe packages for providing mutual contacts of a decreased slip, betweenat least some of respective packages contacting each other in the stack.The stacking can further include applying suitable stack covers, forexample, stretch hoods or stretch wraps or shrink hoods or shrink wraps.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. is a schematic side view of an apparatus for forming an antislipflexible material.

FIG. 2. is a schematic side view of a powder applicator.

FIG. 3. is a schematic side section of a powder applicator.

FIG. 4. is a schematic side view of an apparatus for forming an antislipflexible material.

FIG. 5. is a schematic side view of an apparatus for forming an antislipflexible material.

FIG. 6. is a side view of a provided first layer.

FIG. 7. is a top view of a provided first layer on the release surfacebelt.

FIG. 8. is a schematic side view of a part of an apparatus for formingan antislip flexible material.

FIG. 9. is a side view of an antislip flexible material.

FIG. 10. is a perspective view of an antislip flexible material.

FIG. 11. is a top view of an antislip flexible material.

FIG. 12a . is a perspective view of an antislip flexible material.

FIG. 12b . is a perspective view of a packaging bag of an antislipflexible material.

FIG. 12c . is a perspective view of a packaging bag of an antislipflexible material.

FIG. 12d . is a perspective view of a packaging wrap of an antislipflexible material.

FIG. 12e . is a perspective view of a packaging bag of an antislipflexible material.

FIG. 12f . is a perspective view of a packaging bag of an antislipflexible material.

FIG. 12g . is a perspective view of a packaging wrap of an antislipflexible material.

FIG. 13. is a side view of an antislip flexible material.

FIG. 14. is a side view of an antislip flexible material.

FIG. 15. is a side view of an antislip flexible material.

FIG. 16. is a top view of an antislip flexible material.

FIG. 17. is a side view of a provided first layer.

FIG. 18. is a side view of an antislip flexible material.

FIGS. 19a-19c are schematic side sections of an automatic bag 3 placingapparatus, according to the background art, implementing an automaticbag 3 placing process according to the background art. FIG. 19a shows aphase of the aforementioned background-art automatic bag 3 placingprocess in which a vacuum head 78 approaches, from above, a bag mouth 5of a top bag 3 in a stack of empty layflat bags 3. FIG. 19b shows asubsequent phase of the same process in which the vacuum head 78 haspicked up the bag mouth 5 of the top bag 3 and starts to pull it off theother bags 3. FIG. 19c shows a subsequent phase of the same process inwhich the vacuum head 78 has pulled the top bag 3 off the other bags 3.

FIGS. 20a-20d include schematic side sections of an automatic bagplacing apparatus implementing an automatic bag 3 placing process inwhich a stack of empty bags 3 contains the bags 3 in a form in whicheach bag 3 is individually folded in a way in which the bag bottom 4 ismade parallel and adjacent the bag mouth 5. FIG. 20a shows a phase ofthe aforementioned automatic bag 3 placing process in which a vacuumhead 78 approaches, from above, a bag mouth 5 of a top bag 3 in thestack of empty bags 3. FIG. 20b shows a subsequent phase of the sameprocess in which the vacuum head 78 has picked up the bag mouth 5 of thetop bag 3 and starts to pull it off the other bags 3. FIG. 20c shows asubsequent phase of the same process in which the vacuum head 78 haspartly pulled the top bag 3 off the other bags 3. FIG. 20d shows asubsequent phase of the same process in which the vacuum head 78 haspulled the top bag 3 off the other bags 3.

FIGS. 21a-21d include schematic side sections of an automatic bagplacing apparatus implementing an automatic bag 3 placing process inwhich in a stack of empty bags 3 the empty bags 3 are prepared in a wayin which their bag bottoms 4 are positioned higher than their bag mouths5. FIG. 21a shows a phase of the aforementioned automatic bag 3 placingprocess in which a vacuum head 78 approaches, from above, a bag mouth 5of a top bag 3 in the stack of empty bags 3. FIG. 21b shows a subsequentphase of the same process in which the vacuum head 78 has picked up thebag mouth 5 of the top bag 3 and starts to pull it off the other bags 3.FIG. 21c shows a subsequent phase of the same process in which thevacuum head 78 has partly pulled the top bag 3 off the other bags 3.FIG. 21d shows a subsequent phase of the same process in which thevacuum head 78 has pulled the top bag 3 off the other bags 3.

FIGS. 22a-22c include schematic side sections of an automatic bagplacing apparatus implementing an automatic bag 3 placing process. FIG.22a shows a phase of the aforementioned automatic bag 3 placing processin which a vacuum head 78 approaches, from above, a bag bottom 4 of atop bag 3 in the stack of empty bags 3. FIG. 22b shows a subsequentphase of the same process in which the vacuum head 78 has picked up thebag bottom 4 of the top bag 3 and a separating sheet 70 is started to beinserted, pulled in from the direction of the bag bottom 4, under thetop bag 3. FIG. 22c shows a subsequent phase of the same process inwhich the separating sheet 70 is fully inserted under the top bag 3.

FIG. 23. is a schematic side section of a portion of an automatic bagplacing apparatus.

FIG. 24. is a perspective view of a packaging bag of an antislipflexible material.

FIG. 25. is a side section of a stack of packages.

FIG. 26. is a side section of a stack of packages.

FIG. 27. is a photograph of an antislip flexible material.

FIG. 28. is a photograph of a skidproofing material.

FIG. 29. is a photograph of an antislip flexible material.

FIG. 30. is a photograph of an antislip flexible material.

FIG. 31. is a photograph of an antislip flexible material.

FIG. 32. is a photograph of an antislip flexible material.

DETAILED DESCRIPTION EXAMPLES Example 1: Apparatuses

See the Figures, particularly FIGS. 1-5, 7 and 8. The apparatus ofFIG. 1. includes a polytetrafluoroethylene (PTFE) -coated glass fabricbelt 8 whose outer surface constitutes the release surface 45. There areheating panels 33 for heating the opposite, inner surface of the belt 8.Above the belt 8 there is a powder applicator 47 suitable to applypolymer powder 46 onto the hot release surface 45. The powder applicator47 can be, for example, a scatter coater unit. The powder applicator 47,in general, can preferably include a horizontal sieve, shaken preferablyin a direction parallel with the running direction 67 of the belt 8, foran even distributing of the powder granules 49 on the belt 8 (notshown). The belt 8 is driven around rolls, one of the rolls, a nip roll37 forming a nip 36 with another nip roll 37. The two nip rolls 37 aresuitable to precisely compress the release surface 45 and the carrier 13in the nip 36 between them. The carrier 13 is unwound from a reel andrewound onto another reel, and passes the nip 36 and a cooling unit 22in-between. (Alternatively, an inline operation is possible with otherprocessing machines before and/or after the apparatus; not shown.) Thecooling unit 22 is a set of rolls supporting the carrier 13 withouttouching its front surface 14. The belt 8 is made to revolve in a belt 8running direction 67 and the carrier 13 is pulled with the same speed ina carrier 13 running direction 67. The powder applicator 47 appliespowder granules 49 of the second polymer onto the hot release surface45. By the time the powder granules 49 reach the nip 36, they are formedinto discrete particles 39, tacky from being hot. In the nip 36, theparticles 39 are transferred to the carrier front surface 14 and bondedto the front surface 14, while cooled to solidify, in the cooling unit22 before the rewinding. Because of the small distance between the hotrelease surface 45 and the powder applicator 47, the powder applicator47 can be provided with a heat shield 32 below the powder applicator 47.The heat shield 32 could be two cross directionally arranged rows ofstaggered brass tubes connected to a cooling fluid. There are air shieldwalls 1 protecting the powder applicator 47 from hot air draft from thedirection of the release surface 45. FIG. 2. shows a possible embodimentof the powder applicator 47. A heat shield 32 (a fluid cooled plate)separates a powder conveyor 48 and the release surface 45. The powder 46comes down on the powder conveyor 48. The powder conveyor 48 can, forexample, be a belt conveyor, or a stationary surface or a surface thatis shaken. FIG. 3. shows another possible embodiment of the powderapplicator 47, in side section. It includes a container 17 whose wall 18has one or more openings 19 in it. The one or more openings 19 can be acontinuous gap, or one or more shaped, for example, circular, orifices.The powder 46 is contained in the container 17 and fed onto the releasesurface 45 through the opening 19. The opening 19 has an opening size 2preferably significantly greater than a thickness 21 of the wall 18. Thecontainer 17 can optionally be shaken, for example in the shown shakingdirection 72. There can be a heat shield 32 under the container 17. FIG.4. shows another possible embodiment of the apparatus. The belt 8 isarranged in a vertical orientation, with the nip 36 at its lower end.The powder applicator 47 applies, virtually sticks, the powder 46 ontothe release surface 45 running in a belt 8 running direction 67,vertically upward. The powder applicator 47 can be, for example, a spraygun, or a (e.g., belt, or vibrational) conveyor and can preferably touchthe release surface 45 (in which case it needs to be internally cooled)(not shown). The powder applicator 47 applies the powder 46 inintermittent spots corresponding to the carrier 13 being provided to thenip 36, by a supporting conveyor 77, in the form of intermittentlyprovided individual bags 3. (Alternatively, the powder application couldbe continuous if the individual bags 3 were provided to form acontinuous surface; not shown.) The belt 8 and the supporting conveyor77 run synchronously, which can be a continuous or intermittent running.The apparatus of FIG. 5. differs from that of FIG. 4. in that there thebelt 8 is arranged in a triangle shape.

Example 2: Method for Forming an Antislip Flexible Material 2 andAntislip Flexible Material 2 (Film Carrier 13)

See the drawings, particularly FIGS. 6-12. This example is based onactual manufacturing results. A photograph of an antislip flexiblematerial 2, very similar to that described in this example, is in FIG.27. A photograph of a 20×20 mm piece of the skidproofing material 73that we use is in FIG. 28. For forming an antislip flexible material 2,we provide a flexible carrier 13, which is a polyethylene film tube of awall thickness of about 100 micrometres. It is suitable, for example,for a form-fill-seal (FFS) packaging of individually quick frozenvegetables for making packages of 25 kg filling weight per bag 3. Theaverage surface mass of the carrier 13 is about 186 g/m². (If we used asingle sheet of the film instead of the mentioned tube then the averagesurface mass of the carrier 13 would be about 93 g/m².) Its frontsurface 14 is one of its outer main surfaces at a layflat state of thetube. The surface energy of the front surface 14 is about 33 mJ/m²(without any surface pre-treatment applied). The carrier 13 fullyconsists of a polyethylene blend of linear low density polyethylene andlow density polyethylene, as the thermoplastic first polymer. Themelting temperature of the first polymer is about 122° C. and thesoftening temperature of the first polymer is about 102° C. We providethe carrier 13 at a temperature of 20° C. We provide a hotpolytetrafluoroethylene (PTFE) release surface 45 of a first temperatureof 250° C., measured with an infrared thermometer. The surface energy ofthe release surface 45 is about 18.5 mJ/m². The release surface 45 isessentially flat on the macro scale and is very slightly textured, onthe micro scale, in accordance with the pattern of the glass fabric coreof the PTFE-coated glass fabric belt 8 whose outer surface constitutesour release surface 45. The pattern is independent from the distributionof the discrete particles 39 of the provided first layer 29. We providethe first layer 29 of the discrete particles 39 by scattering from theair onto the hot release surface 45, of the first temperature of 250°C., a powder 46 (ground from pellets) of a linear medium densitypolyethylene, the second polymer, of a melt mass flow rate of 4.0determined at 190° C. under a load of 2.16 kg in accordance with ISO1133-1. Thereby we provide the first layer 29 of the discrete particles39 sitting on the release surface 45 with a random distribution.(Alternatively, we could use flame spraying equipment, working from apowder 46 or a rod or a wire of the second polymer, for spraying fromthe air liquid and/or semi-liquid portions of the second polymer ontothe release surface 45. Further alternatively, we could transfer apowder 46, or a solution, of the second polymer, colder than itssoftening temperature, on a surface of a fluid-cooled conveyor, such asa belt conveyor or a vibrational conveyor, whose cooled discharge end isin contact with the hot release surface 45 in order to bring onto therelease surface 45, other than from the air, portions of the secondpolymer colder than the softening temperature of the second polymer.)The surface energy of the second polymer is about 33 mJ/m². The size ofthe powder 46 is 0-300 micrometres. The average surface mass of thescattered powder 46, and of the discrete particles 39 provided, is about8 g/m². We keep the discrete particles 39 of the provided first layer 29sitting on the hot release surface 45 for about 9.29 seconds which islong enough to provide virtually all of the discrete particles 39 in anat least semiliquid state and having first contact angles 28, estimatedto be between about 59 and 64 degrees, with the release surface 45. As aresult of originating from a powder 46 ground from pellets and ofspending the mentioned time sitting on the hot release surface 45, everyprovided discrete particle 39, as well as every roughening projection 50formed from the particles 39, is virtually fully molecularly unoriented.The size of the discrete particles 39 is about 80-1000 micrometres, thelatter a size of a particle 39 including a plurality of merged powdergranules 49. The typical particle 39 size, in a top plan view, is about300 micrometres. As concerning the closeness of the discrete particles39, an average distance 42 between centres of neighbouring discreteparticles 39 is about 2000 micrometres. The discrete particles 39,sitting on the hot release surface 45, project from the hot releasesurface 45 to their corresponding terminal ends 43. The outer surface ofthe discrete particles 39 of the provided first layer 29 is made up of afirst portion 30 contacting the release surface 45 and a second portion69 out of a contact with the release surface 45, an area of the secondportion 69 being substantially greater than an area of the first portion30 in each of the provided discrete particles 39. In virtually all ofthe discrete particles 39 the particle height 40 equals at least 0.5times a smallest top-plan-view extent 42 of the particle 39. In theprovided first layer 29 all of the discrete particles 39 are in theirentireties of a temperature, the second temperature, of about 250° C.,whereas the Vicat softening temperature (A/50 N) of the second polymeris 114° C., which causes in the first layer 29 a tackiness of theentireties of the discrete particles 39, including their terminal ends43. We provide two nip rolls 37 and press the carrier 13 and the hotrelease surface 45 toward each other within a nip 36 between the two niprolls 37 to provide the contact between the carrier front surface 14 andthe tacky terminal ends 43 of the particles 39, exerting on the carrier13 a nip 36 pressure of 0.784 N/lineal cm. During the contact we applyan average compression pressure of 2904 Pa. We keep the carrier 13(i.e., the film tube) and the release surface 45 (i.e., the PTFE-coatedglass fibre belt 8) running at uniform line speeds between the nip rolls37. We provide the nip roll 37 pressing the release surface 45 towardthe front surface 14 with a heat resistant silicone rubber surface andwe form the nip roll 37 surface pressing the carrier 13 toward therelease surface 45 from a foamed elastomer whose hardness we select toprovide (at the mentioned nip 36 pressure) an abutting, between thefront surface 14 and the release surface 45 with the mediation of thefirst layer 29, of an abutting length 81 of 27 mm, the abutting length81 measured in the running direction 67. See FIG. 8. The diameters ofthe nip rolls 37 can depend on the general layout, for example, belt 8length and-width etc. of the apparatus, but in general, the diameterscan be for example between 60 mm and 600 mm. We keep the endless belt 8alternatingly shifted, perpendicularly to the running direction 67,between its two lateral end positions 9, providing a lateraldisplacement 10 of the belt 8 between the two end positions 9, thelateral displacement 10 being about 30 mm, which is greater than 10times the average of the inter-particle distances 35. We select a linespeed to provide a contacting time of about 0.0235 seconds, during whichcontacting time we keep the front surface 14 in contact with at least amajority of the tacky discrete particles 39 sitting on the hot releasesurface 45. The contacting time divided by the average surface mass ofthe carrier 13 is provided to be about 0.0001263 s·m²/g. With thementioned parameters of the process we reach the following result. Thecarrier 13 is not impaired, whatsoever, from the heat of the releasesurface 45. (For a comparison, in the same configuration a40-micrometre-thick polyethylene single layer sheet film carrier 13 wasexperienced to warp, wrinkle, cross-shrink and stretch to an extent thatrules out selling the film product, i.e., the thin film was spoiled bythe heat of the release surface 45.) At most that small minority of thediscrete particles 39 remains out of the contact that is constituted bythe smallest powder granules 49 scattered (they will probably be pickedup in the next revolutions of the belt 8 as soon as a new powder granule49 falls upon them). Thereby we stick the contacting discrete particles39 of the first layer 29 to the front surface 14 and thereafter removethe carrier 13, and therewith virtually all of the tacky particles 39stuck to its front surface 14, from the hot release surface 45 andthereby we provide the carrier 13 with a coating 16 of a hot state.After the removing, the free surface of the hot coating 16 can(preferably) be left free from any contact until it cools down, but itis also possible to contact it with a (preferably cooled) surface whenthe coating 16 is still hot and tacky, for example, in order of furthershaping the coating 16 for providing, for example, substantially flattops 62 or structured tops in the roughening projections 50 (contactingnot shown). Due to the provided surface energies mentioned, the adhesiveforce between the front surface 14 and the contacted tacky particles 39is greater than the adhesive force between the release surface 45 andthe contacted tacky particles 39. Due to the sufficiently low melt massflow rate (i.e., to the sufficiently great melt viscosity) of the secondpolymer, in the particles 39, the cohesive force of the contacted tackyparticles 39 is greater than the adhesive force between the releasesurface 45 and the contacted tacky particles 39 resulting in a virtuallycomplete removing of the contacted tacky particles 39 from the releasesurface 45 wherein certainly less than 1% of the polymer of contactedtacky particles 39 is estimated to remain on the release surface 45during one removing operation. The coating 16 does not penetrate orenter into the carrier 13, except for an intermolecular diffusionbetween the front surface 14 and the coating 16. Utilising a heat energyof the hot coating 16, we form a bond 12 between the carrier 13 and thecoating 16. Thereby we provide an antislip coated flexible material 2including the carrier 13 and the coating 16 bonded thereto. Thecontacting time is short enough for preventing the carrier 13 from beingdistorted or spoiled to any extent by the heat of the release surface45. All portions of the carrier 13, except its portions adjacent to thehot particles 39 stuck to its front surface 14, are prevented frommelting or softening between the bringing into the contact and theforming of the bond 12. Providing both the first temperature and thesecond temperature above a fusing temperature at which the first polymerand the second polymer are capable of fusing together, we utilise theheat energy of the hot coating 16 of the discrete roughening projections50 for heating carrier parts 15 adjacent to the roughening projections50, sufficiently to melt its substance, i.e., the first polymer, in theheated carrier parts 15, and thereafter allow the carrier 13 and theroughening projections 50 to spontaneously cool into a solid state forforming the final bond 12. Thereby we fuse, and in particular, weld, theroughening projections 50 with the carrier 13. This bond 12 proves to bedefinitely strong against a breaking off of the roughening projections50. Probably due to a local and surficial slight heat shrinking of thecarrier front surface 14, the front surface 14 appears to be providedwith respective depressions 23 under the feet 55 of some of theroughening projections 50, particularly under the larger ones, whereinthe depth of the depressions 23 is small enough to keep the widest part66 of the roughening projections 50 above the rest of the front surface14 in each side view of the roughening projection 50. The carrier 13 inits entirety constitutes a heat shrinkable second layer including thethermoplastic first polymer, which surely shrinks above a temperature of122° C., therefore the first temperature is well above the shrinkingtemperature of the second layer. The carrier 13 is heat sensitive enoughto completely lose its stability if heated completely to the firsttemperature. The contacting time is sufficiently short for preventingthe carrier 13 from any contracting from any of its original dimensions.Also, in the antislip coated flexible material 2, an average surfacemass of the coating 16 is about 8 g/m² which only equals about 0.043times an average surface mass of the carrier 13 which also contributesto the protecting of the carrier 13 from spoiling from excess heat. Weprovide the heat energy of the hot coating 16 suitably low formaintaining, without any forced cooling (such as for example achill-roll cooling), a virtually intact breaking strength of the carrier13, far sufficient for a rewinding of the carrier 13. During thecontacting time a major portion of the front surface 14, betweenneighbouring tacky particles 39, is kept out of a contact with therelease surface 45. As a result of the relatively low surface mass ofthe coating 16 and the relatively great discrete particle size 41, weform a discontinuous coating 16 of the antislip coated flexible material2. The coating 16 occupies about 7.8% of the area of the antislip coatedflexible material 2 in a top plan view. The formed coating 16 includes amultiplicity of discrete roughening projections 50 projecting from thefront surface 14 of the carrier 13, each roughening projection 50provided with a foot 55, the foot 55 being the end of the rougheningprojection 50 bonded to the carrier 13. We provide many of theroughening projections 50 with a second contact angle 68 of betweenabout 130 and 140 degrees with the front surface 14 in a plurality ofside views of the roughening projection 50. To provide flat-toppedroughening projections 31, we provide almost all of the rougheningprojections 50 with a substantially flat top 62 forming an edge 53completely surrounding the substantially flat top 62, the edge 53 inmany cases essentially forming a circle. In almost all of the rougheningprojections 50 in a plurality of side views of the roughening projection50 at least one contour line part 52 of the roughening projection 50,connecting the foot 55 and the edge 53, is formed to be strictly convexfrom outside, these are the strictly convex contour line parts 61. In atleast one side view of many roughening projections 50 the ratio of thewidth of the substantially flat top 63 to the foot width 56 is providedbetween 1 and 1.10. In a majority of the roughening projections 50 thearea of the foot 55 is provided to be smaller than the area of thesubstantially flat top 62. In a majority of the roughening projections50 the roughening projection 50 is provided with an edge angle 54 beingan angle, measured through the roughening projection 50, closed betweenthe substantially flat top 62 and a mantle surface 59 extending from theedge 53 to the foot 55, where the edge angle 54 is typically smallerthan 90 degrees. In many roughening projections 50 the edge angle 54 isabout 75 degrees. Many roughening projections 50 are formed to be astrictly tapering roughening projection 74, strictly tapering from theedge 53 to the foot 55 in each side view of the roughening projection50. We provide a majority of the roughening projections 50 with a hiddensurface portion 58 being a portion of an outer surface of the rougheningprojection 50 which the roughening projection 50 covers from a viewer ina top plan view of the antislip coated flexible material 2 taken fromabove the roughening projections 50. These roughening projections 50have at least one undercut 65, and very many of them include at leastone area 51 immediately above the undercut 65 forming a separation 71between the at least one area 51 and the front surface 14 which isgreater than 20 micrometres. The roughening projections 50 inherit fromthe discrete particles 39 their random distribution in the top plan viewof the antislip coated flexible material 2. As a result of the providedpowder 46 of the second polymer not being fully homogeneous in size, weform the roughening projections 50 of random top-plan-view sizes 64.Virtually none of the roughening projections 50 are provided with atop-plan-view size 64 smaller than 40 micrometres or greater than 6 mm.We provide the average, or typical, roughening projection top-plan-viewsize 64 between 250 micrometres and 800 micrometres. If the appliedscatter coating operation provides a distribution of the particles 39homogeneous enough then only few of the powder granules 49 stick andmerge together to form particles 39, and roughening projections 50, ofrelatively greater top-plan-view sizes 64 or relatively greatertop-plan-view aspect ratios and the vast majority of the rougheningprojections 50 can originate from such particles 39 as originate from asingle powder granule 49, which roughening projections 50 appear to havetop-plan-view aspect ratios between 1.0 and 1.6. (Aspect ratioessentially means a ratio of the top-plan-view size 64 to the smallesttop-plan-view extent 60 of the roughening projection 50 in a top planview of the antislip coated flexible material 2 taken from above theroughening projections 50.) That can result in the multiplicity of theroughening projections 50 having an average top-plan-view aspect ratioof less than 1.6, about 1.2 or even less than that. Many rougheningprojections 50 are not fully circular in the top plan view and they showthat the roughening projections 50 are formed of random orientations ina top plan view of the antislip coated flexible material 2. We form theroughening projections 50 projecting from their respective feet 55 torespective projection heights 57 with a substantially uniform projectionheight 57 of about 110 micrometres and with substantially variedsmallest top-plan-view extents 60 in which the coefficient of variationof the smallest top-plan-view extents 60 is at least 2.0 times thecoefficient of variation of the projection heights 57. The tops ofvirtually all of the roughening projections 50 are essentially inalignment along a plane 44 parallel with a general plane of the frontsurface 14. In many of the roughening projections 50, a smallesttop-plan-view extent 60 of the roughening projection 50 is formed toequal at least 10 times the projection height 57. The provided antislipcoated flexible material 2 is capable of a slip-decreasing mechanicalinterlock in a shearing direction with a skidproofing material 73, of anordinary polypropylene spunbonded nonwoven fabric of an average surfacemass of 17 g/m² and filament thickness of between 25 and 30 micrometres,due to the roughening projections 50 having suitable closeness andgeometric features with respect to the skidproofing material 73 forforming mechanical bonds with the filaments of the skidproofing material73 in the shearing direction. According to our test results, a staticfriction between two specimens of the antislip coated flexible material2, with a specimen of the skidproofing material 73 placed between thespecimens of the antislip coated flexible material 2, is suitably highto resist sliding in an inclined-plane-type static-friction test of 75degrees angle according to the TAPPI T 815 standard. We measured thestatic coefficient of friction between two specimens of the antislipcoated flexible material 2, with a specimen of the skidproofing material73 placed between the specimens of the antislip coated flexible material2 to be 10.2 at a pressure of 1539 Pa, otherwise according to ISO 8295.This selected pressure value practicably simulates pressure conditionsin a real life stack of bag 3 packages, and we note that the test resultof 10.2 is a considerably great value. The antislip coated flexiblematerial 2 does not essentially stick to the skidproofing material 73against a lifting or peeling separation, they show a negligible mutualblocking load. Due to the roughening projections 50 being free frommolecular orientation and due to a relatively low melt mass flow rate ofthe second polymer, the mentioned frictional effectiveness of theroughening projections 50 is, as we found, maintained even after a heatshrinking of the antislip coated flexible material 2. Namely, we used aBosch PHG 630 DCE hot air gun (on its 6th temperature degree, withmaximum air speed, with an air temperature above 200° C., for 130seconds) to shrink the film to simulate a shrink wrap shrinkingoperation. We let the film shrink 10% from its original dimensions inall directions (the antislip flexible material 2 shows a heatshrinkability of at least 30% in all directions). The result is that thestatic coefficient of friction, with the skidproofing material 73, wasvirtually left intact by the shrinking. Also, a difference in the shapesof the roughening projections 50, before and after the heat shrinking,is not noticeable visually. The film appears to shrink as if there werenot any roughening projections 50 in it, i.e., its shrinking behaviouris virtually not affected by the roughening projections 50. We form theroughening projections 50 occupying a stripe 76 in the middle of themain outer surface of the layflat film tube, both on its front side andits back side, the roughening projections 50 looking toward an outside 6of the tube. On the back side of the endless tube we fix an endlessstrip 75 of the skidproofing material 73, covering the roughened surfacepart of the back side. See FIG. 12a . The fixing we do, for example,with fibre-spayed hot melt adhesive or, preferably, with extrusionlamination, in which we use narrow continuous beads of extrudedpolyolefin polymer to encapsulate the fibres of the nonwoven and fix itto the film, compressing the film/melt/nonwoven sandwich between cooledmetal rolls, which do not stick to the melt even if it strikes throughthe nonwoven. We form, with cross welding and cutting, both packagingbags 3, namely 25-kg heavy duty bags 3, and packaging wraps 79, namelyshrink wraps 79 (for example for a shrink-collating wrap 79 for cans),from the tube that has been provided with the skidproofing material 73.One side of the bags 3 has the skidproofing material 73 fixed to it, andthe other, opposing side of the bags 3 is a roughened side 7, with theroughening projections 50 projecting toward the outside 6 of the bag 3,capable of gripping with the skidproofing material 73. FIG. 12b . showsthe roughened side 7 of the bag 3, FIG. 12c . shows the opposite side ofthe bag 3, with the skidproofing material 73, FIG. 12d . shows theprepared wrap 79 ready to be shrunk, with the roughening projections 50projecting toward the outside 6 of the wrap 79. FIG. 12e . shows theroughened side 7 of a bag 3, in which the roughening projections 50occupy a spot in the middle of the bag 3 surface and FIG. 12 f. showsthe opposite side of the same bag 3, wherein the skidproofing material73 occupies a spot in the middle of the bag 3 surface. Such pieces ofthe skidproofing material 73 could, for example, be applied to the tubewith a slip cut unit. FIG. 12g . shows the wrap 79 of FIG. 12d alreadyshrunk onto a package of cans, with the roughening projections 50projecting toward the outside 6 of the wrap 79.

Example 3: Method for Forming an Antislip Flexible Material 2 andAntislip Flexible Material 2 (Coated Fabric 25 Carrier 13)

See the drawings, particularly FIGS. 6-13. This example is based onactual manufacturing results. A photograph of the antislip flexiblematerial 2 is in FIG. 29. In the photograph, a folded edge of theroughened fabric 25 can be seen, with roughening projections 50 in sideview. The “3 mm” line shows the width of a tape 26 of the fabric 25. Thefibres on the left are fibres torn off the skidproofing material 73during several different shearing tests. The small dust granules arefrom fine dust pollution. This example essentially differs from Example2 as follows. For forming an antislip flexible material 2, we provide aflexible carrier 13, which is a tube of circularly woven polypropylenefabric 25, woven from polypropylene tapes 26, of a fabric 25 surfacemass of 75 g/m², extrusion-coated on both of its main outer (i.e., frontand back) surfaces with a polypropylene layer of a surface mass of 30g/m². (Alternatively, the tube could be laminated on both of its mainouter surfaces with a polypropylene film, for example biaxially orientedpolypropylene film.) The average surface mass of the tubular carrier 13is thus 210 g/m². The surface energy of the front surface 14 is about 30mJ/m² (without any surface pre-treatment applied). The meltingtemperature of the first polymer is about 170° C. and the softeningtemperature of the first polymer is about 125° C. We provide the releasesurface 45 of a first temperature of 255° C. We provide the first layer29 of the discrete particles 39 by scattering from the air onto the hotrelease surface 45, of the first temperature of 255° C., a powder 46(ground from pellets) of polypropylene, the second polymer, of a meltmass flow rate of 14.0 determined at 230° C. under a load of 2.16 kg inaccordance with ISO 1133-1. The surface energy of the second polymer isabout 30 mJ/m². The size of the powder 46 is 0-300 micrometres. Theaverage surface mass of the scattered powder 46, and of the discreteparticles 39 provided, is about 5 g/m². We keep the discrete particles39 of the provided first layer 29 sitting on the hot release surface 45for about 8.0 seconds which is long enough to provide virtually all ofthe discrete particles 39 in an at least semiliquid state and havingfirst contact angles 28, estimated to be between about 59 and 64degrees, with the release surface 45. In the provided first layer 29 allof the discrete particles 39 are in their entireties of a temperature,the second temperature, of about 255° C., whereas the Vicat softeningtemperature (A, ISO 306) of the second polymer is 128° C., which causesin the first layer 29 a tackiness of the entireties of the discreteparticles 39, including their terminal ends 43. We exert on the carrier13 a nip 36 pressure of 0.735 N/lineal cm. During the contact we applyan average compression pressure of 2722 Pa. We select a line speed toprovide a contacting time of about 0.0203 seconds. With the mentionedparameters of the process we reach the following result. The contactingtime is short enough for preventing the carrier 13 from being distortedor spoiled to any extent by the heat of the release surface 45. We fuse,and in particular, weld, the roughening projections 50 with the carrier13. This bond 12 proves to be definitely strong against a breaking offof the roughening projections 50. The fabric 25 of the carrier 13 isleft free of fused bonds 12 in overlaps 38 between its tapes 26 underthe roughening projections 50. Not any depressions 23, under the feet 55of the roughening projections 50, can be seen. In a majority of theroughening projections 50 the edge angle 54 is typically smaller than 90degrees. In many roughening projections 50 the edge angle 54 is about 75degrees. As a result thereof, many flat-topped roughening projections 31have suitable geometric features with respect to the tapes 26, exposedin the total internal tube surface of the carrier 13, for forming withmany of the exposed tapes 27 a definite slip-decreasing mechanicalinterlock. According to results of inclined-plane-type static-frictiontests of 60 degrees angle according to the TAPPI T 815 standard, astatic friction between two specimens of the antislip coated flexiblematerial 2, with a specimen of the skidproofing material 73 placedbetween the specimens of the antislip coated flexible material 2, issuitably high to resist the sliding (i.e., the sled assembly does notslide but stays in place). Further, the mentioned static friction issuitably high to resist the sliding immediately after a preparation, theice test preparation, the ice test preparation including maintaining inthe carrier 13, and the roughening projections 50, of a first one of thetwo specimens of the antislip coated flexible material 2 a thirdtemperature of about −20° C. while exposing the carrier front surface 14and the roughening projections 50 to air of a temperature of about 3° C.and of a relative humidity of 100%, completed with a dense fog of watergenerated in the ambient air with an ultrasonic air humidifier, for apreparation time of as long as 19 minutes and the ice test preparationfurther including providing a second one of the two specimens of theantislip coated flexible material 2 and the specimen of the skidproofingmaterial 73 of the third temperature. The static friction remainssuitably high despite the fact that the front surface is white withfrost after the 19-minute preparation time. An even longer preparationtime is applicable without providing the fog. It proves that thefriction of the antislip coated flexible material 2 is fairlyinsensitive to an ice buildup on its roughened surface, which makes itparticularly useful for frozen food packaging bags 3 and timber wraps79. We measured the static coefficient of friction between two specimensof the antislip coated flexible material 2, with a specimen of theskidproofing material 73 placed between the specimens of the antislipcoated flexible material 2 to be 10.3 at a pressure of 1539 Pa,otherwise according to ISO 8295. On the other hand, according to resultsof our blocking tests, the antislip flexible material 2 has with theskidproofing material 73 an average blocking load of 2.94 gramsaccording to the standard ASTM D 3354-96, after a preparation includingcompressing the samples with a pressure of 1500 Pa immediately prior tothe blocking load test. If we also include, in the preparation, arelative rotation, during the compression, of the two specimens with ±8degrees angle back and forth repeated three times, then the result isthat the average blocking load is not more than 19.4 grams. The staticcoefficient of friction, with the skidproofing material 73, is found tobe virtually left intact by a heat shrinking of the antislip coatedflexible material 2. We form the roughening projections 50 occupying astripe 76 in the middle of the main outer surface of the layflat filmtube, both on its front side and its back side, the rougheningprojections 50 looking toward an outside 6 of the tube. On the back sideof the endless tube we fix an endless strip 75 of the skidproofingmaterial 73, covering the roughened surface part of the back side. Thefixing we do, preferably, with extrusion lamination. We form, with(preferably ultrasonically) cross sewing and cutting, packaging bags 3,namely 25-kg heavy duty bags 3, from the tube that has been providedwith the skidproofing material 73. One side of the bags 3 has theskidproofing material 73 fixed to it, and the other, opposing side ofthe bags 3 is a roughened side 7, capable of gripping with theskidproofing material 73. We prepared test blocks 11 (simulating frozenfish blocks 11) of a size of 53×53×10 cm and cooled them to −20° C. Wefilled the bags 3 with one block 11 each and closed the bags 3 withintermittent cross welding (to let the air pressure out through theintermittent welding seam). To perform the stack tilting test, we putthe packages on top of each other, centrally, on a plate and tilted theplate into a slanting orientation closing with the horizontal an angleof 45 degrees, and then turned the plate back to horizontal. Then wehorizontally dragged the top package off from the bottom package (forwhich we had to somewhat tilt the top package to stand it to its edgeotherwise it would have been virtually impossible to slide it) and thenrepeated the tilting test with success again. (Alternatively, when weused a polypropylene powder 46 of a size of 0-300 micrometres and of amelt mass flow rate of 8.5 g/10 min, in a surface mass of about 16.7g/m² and with a heating time of about 12.5 seconds with a nip 36pressure of 0.274 N/lineal cm and an estimated contacting time of about0.02 seconds we got the results of inclined-plane-type static-frictiontests made with a steel sled of a height of 40 mm but otherwiseaccording to the TAPPI T 815 standard as follows: a static frictiondirectly between two specimens of the antislip coated flexible material2, without any skidproofing material 73 placed inbetween, was measuredto be above 1.34, with some specimen pairs showing a coefficient offriction of 1.68. The friction proved to be insensitive to a presence ofcement dust pollution between the surfaces. The coated base fabric 25without roughening shows a static coefficient of friction of 0.45. As afurther improved alternative, we could use a very narrow size fractionof powder 46 in order of an even better control over the process (e.g.in order of a very even and uniform contacting and pressing, and a morecomplete removing from the release surface, of the melted discreteparticles 39) and in order of an even greater static coefficient offriction between the roughened surfaces. For example, a powder 46 of asize of between 100 micrometres and 110 micrometres is advantageous. Or,alternatively, the powder's 46 size interval can be defined between anytwo, lower and upper, limit values whereas the difference between thelimit values is equal to or lower than one or both of 10, or even 5,micrometres and 10, or even 5, percent of the lower limit value.)

Example 4: Method for Forming an Antislip Flexible Material 2 andAntislip Flexible Material 2 (Uncoated Fabric 25 Carrier 13)

See the drawings, particularly FIG. 14. This example is based on actualmanufacturing results. A photograph of the antislip flexible material 2is in FIG. 30. This example essentially differs from Example 3 asfollows. For forming an antislip flexible material 2, we provide aflexible carrier 13, which is a circularly woven polypropylene fabric 25tube, woven from polypropylene tapes 26, of a fabric 25 surface mass of65 g/m² (not extrusion-coated). The average surface mass of the tubularcarrier 13 is thus 130 g/m². We provide the release surface 45 of afirst temperature of 255° C. We use a rotational-moulding powder 46 ofpolypropylene, the second polymer, of a melt mass flow rate of 15determined at 230° C. under a load of 2.16 kg in accordance with ISO1133-1. The size of the powder 46 is sieved to 0-550 micrometres. Theaverage surface mass of the scattered powder 46, and of the discreteparticles 39 provided, is 14.6 g/m². We keep the discrete particles 39of the provided first layer 29 sitting on the hot release surface 45 for8.0 seconds. In the provided first layer 29 all of the discreteparticles 39 are in their entireties of a temperature, the secondtemperature, of about 255° C. We exert on the carrier 13 a nip 36pressure of 1.225 N/lineal cm. During the contact we apply an averagecompression pressure of 3952 Pa. We select a line speed to provide acontacting time of about 0.0233 seconds. With the mentioned parametersof the process we reach the following result. The contacting time isshort enough for preventing the carrier 13 from being distorted orspoiled to any extent by the heat of the release surface 45. We fuse,and in particular, weld, the roughening projections 50 with the carrier13. The fabric 25 is left free of fused bonds 12 in overlaps 38 betweenits tapes 26 under the roughening projections 50. Not any depressions23, under the roughening projection feet 55, can be seen. We prevent thecoating 16 from penetrating the fabric 25 whatsoever. Many flat-toppedroughening projections 31 have suitable geometric features with respectto the tapes 26, exposed in the total internal and external tubesurfaces of the carrier 13, for forming with many of the exposed tapes27 a definite slip-decreasing mechanical interlock. The rougheningprojections 50 are easier to break off from the front surface 14 than inthe first two examples.

Example 5: Method for Forming an Antislip Flexible Material 2 andAntislip Flexible Material 2 (Film Carrier 13, Elastomeric Coating 16)

See the drawings, particularly FIGS. 15-16. This example is based onactual manufacturing results. A photograph of the antislip flexiblematerial 2 is in FIG. 31. Please note that, in the photograph, both ofthe two layers of a folded product sample are visible, because of thefilm being clear transparent. This example essentially differs fromExample 2 as follows. For forming an antislip flexible material 2, weprovide a flexible carrier 13, which is a clear transparent composite,consisting of a polyamide film and a polyethylene layer, made withextrusion coating, thereon. Its front surface 14 is the polyethylenesurface. The front surface 14 thus consists of low density polyethylene,as the thermoplastic first polymer. The melting temperature of the firstpolymer is about 122° C. and the softening temperature of the firstpolymer is about 102° C. We provide the first layer 29 of the discreteparticles 39 by scattering from the air onto the hot release surface 45,of the first temperature of 253° C., a powder 46 (ground from pellets)of a blend of low density polyethylene and ethylene-vinyl acetate (EVA),the second polymer, of a melt mass flow rate of 40 determined at 190° C.under a load of 2.16 kg in accordance with ISO 1133-1. In order ofavoiding a later blocking of the product, the second polymer isrelatively poor in EVA and is free from tackifiers. The DSC meltingtemperature of the second polymer is between 100° C. and 110° C., whichis considered to be high within EVA-containing polymer grades. The sizeof the powder 46 is 100-500 micrometres. The average surface mass of thescattered powder 46, and of the discrete particles 39 provided, is about7 g/m². We apply a manufacturing line speed of 160 metres per minute. Wenote that this is a considerably great speed in the art, and we can notsee any technical factors preventing, in theory, the skilled person fromfurther increasing the speed for example with applying longer releasesurface 45 belt 8 lengths. We keep the discrete particles 39 of theprovided first layer 29 sitting on the hot release surface 45 for 4.00seconds which is long enough to provide virtually all of the discreteparticles 39 in an at least semiliquid state and having first contactangles 28, estimated to be between about 59 and 64 degrees, with therelease surface 45. In the provided first layer 29 all of the discreteparticles 39 are in their entireties of a temperature, the secondtemperature, of about 253° C., whereas the Vicat softening temperature(A/50 N) of the second polymer is under 100° C., which causes in thefirst layer 29 a tackiness of the entireties of the discrete particles39, including their terminal ends 43. We apply a nip 36 pressure of0.735 N/lineal cm. During the contact we apply an average compressionpressure of 2722 Pa. We apply a contacting time of 0.0101 seconds. Withthe mentioned parameters of the process we reach the following result.We provide virtually each roughening projection 50 with a substantiallyflat top 62, with the edge 53 essentially forming a circle. We providein every side view of a vast majority of the roughening projections 50 aratio of a width 63 of the substantially flat top to a foot width 56from 1 to 1.10. We provide, in the antislip coated flexible material 2,such roughening projections 50 whose average top-plan-view aspect ratiowe estimate to be between 1.0 and 1.1 since they look virtually circularin the top plan view. Since virtually all of the roughening projections50 are of the same (low) height 57, all of the variation of theirrespective volumes (originating from a volume variation of the powdergranules 49) appears in their varied smallest-top-plan-view extents 60.Therefore the coefficient of variation of the smallest top-plan-viewextents 60 is estimated to be well over a triple of the coefficient ofvariation of the projection heights 57. The provided antislip coatedflexible material 2 is measured to have with itself an average blockingload of 13.66 grams in the modified blocking load test. This is a goodvalue and it expresses that the product will virtually not block when itis stored in a warm warehouse. This parameter is the result of thesecond polymer, of the coating 16, having a relatively high meltingtemperature and being free of tackifiers. The provided antislip coatedflexible material 2 is in fact not capable of an essentialslip-decreasing mechanical interlock in a shearing direction with theskidproofing material 73. We measured static and kinetic coefficients offriction (at a pressure of 1539 Pa, otherwise according to ISO 8295, asfollows below) and we found them to be very close to each other in eachcase which, as it is known to the skilled person, provides a desirablebehaviour of the product once it happens to be shear-loaded to an extentwhere it starts to slip. According to our test results, the coefficientof friction of the roughened side 7, with itself, is 0.96, which isconsidered to be a value high enough for many practical applications,and which is economical, with regard to the inexpensive coating 16material, to the low coating 16 weight of 7 g/m² and to the highconversion speed of at least 160 m/minute. The coefficient of frictionof the roughened side 7 with a smooth polyethylene surface is 0.5, wherethe mentioned smooth polyethylene surface has, with itself, acoefficient of friction of 0.44.

Example 6: Method for Forming an Antislip Flexible Material 2 andAntislip Flexible Material 2 (Film Carrier 13, Elastomeric Coating 16)

This example is based on actual manufacturing results. A photograph ofthe antislip flexible material 2 is in FIG. 32. This example essentiallydiffers from Example 5 as follows. We provide a powder 46 (ground frompellets) of a blend of low density polyethylene and ethylene-vinylacetate (EVA), the second polymer, of a melt mass flow rate of 150determined at 190° C. under a load of 2.16 kg in accordance with ISO1133-1. In order of avoiding a later blocking of the product, the secondpolymer is relatively poor in EVA and is free from tackifiers. The DSCmeting temperature of the second polymer is between 97° C. and 108° C.The size of the powder 46 is 100-400 micrometres. The average surfacemass of the scattered powder 46, and of the coating 16 provided, isabout 16.3 g/m². We apply a manufacturing line speed of 80 metres perminute. We keep the discrete particles 39 of the provided first layer 29sitting on the hot release surface 45 for 8.00 seconds which is longenough to provide virtually all of the discrete particles 39 in an atleast semiliquid state and having first contact angles 28, estimated tobe between about 59 and 64 degrees, with the release surface 45. Weapply a nip 36 pressure of 4.9 N/lineal cm. We apply a contacting timeof about 0.024 seconds. With the mentioned parameters of the process wereach the following result. As can be seen in the photograph, manyparticles 39, originating from respective powder granules 49, are madeto merge in the coating 16, but the coating 16 is still discontinuous.This antislip flexible material 2 can be used where greater coefficientsof friction are necessary.

Example 7: Method for Forming an Antislip Flexible Material 2 andAntislip Flexible Material 2 (Printed Film Carrier 13, ElastomericCoating 16)

This example is based on actual manufacturing results. This exampleessentially differs from Example 5 as follows. The carrier 13 we provideis a heavy duty packaging film tube of a recycled polyethylene blendrich in low density polyethylene, of a thickness of 100 micrometres,whose front surface 14 has been printed, with customer graphics, using asolvent-based flexographic ink of an acrylic base. The average surfacemass of the scattered powder 46, and of the coating 16 provided, isabout 5 g/m². We apply a manufacturing line speed of 80 metres perminute. We keep the discrete particles 39 of the provided first layer 29sitting on the hot release surface 45 for 8.00 seconds which is longenough to provide virtually all of the discrete particles 39 in an atleast semiliquid state and having first contact angles 28, estimated tobe between about 59 and 64 degrees, with the release surface 45. Withthe mentioned parameters of the process we reach the following result.Utilising the great heat energy of the hot coating 16 we are able toform a definitely strong bond 12 between the printed carrier frontsurface 14 and the discontinuous coating 16, despite the fact that thesecond polymer, of the coating 16, is free of tackifier. The rougheningprojections 50 appear to be impossible to scrape off, from the printedfilm surface, with a fingernail. Our opinion is that suitably selectedsolvent-based or water-based ink materials, for example of a low heatresistance (for example primarily of acrylic base), may be virtuallypossible to be welded-through in our method, even if the powder 46 usedis polyethylene or polypropylene without EVA or other similar adhesiveagent, though some modification of their pigment colour may happen,which, in the given case, we do not consider an impairing of theproduct. The weldability and colour-keeping of the print can also dependon the kind of pigment it contains. Alternatively, a transparentheat-seal-lacquer layer (printed from, for example, a solvent-based orwater-based polyolefin solution) might also provide a suitable weldingof the coating 16 to the printed-and-lacquered front surface 14.

Example 8: Method for Forming an Antislip Flexible Material 2 andAntislip Flexible Material 2 (Various Shape Examples)

See the drawings, particularly FIGS. 17-18. In FIG. 17. side views ofprovided discrete particles 39 of different shapes can be seen. Firstcontact angles 28 (between particle 39 and release surface 45) can beprovided to be relatively great, i.e., for example at or above 90degrees, if we keep the powder granules 49 sitting on the hot releasesurface 45 for a relatively short time and/or provide a second polymerof a relatively low melt mass flow rate, i.e., for example, lower than4.0. From the illustrated provided discrete particles 39 such rougheningprojections 50 can be formed, see FIG. 18., whose edge angles 54 arerelatively great, i.e., for example at or above 90 degrees.

Example 9: Methods of Use

See FIGS. 19-26. Antislip packaging bags 3, for example those made inExample 3, can be used, among others, in the following ways. FIGS. 19 a,19 b, 19 c illustrate an automatic bag 3 placing process according tothe background art, in side section. A vacuum head 78 picks up the bagmouth 5 of the top bag 3 in a stack of empty layflat bags 3 and pulls itoff the other bags 3. With our current bags 3, made in Example 3, thisoperation is not always possible because the layflat bags 3 do not slipon each other if the roughened side 7 of a first bag 3 should slide onthe skidproofing material 73 fixed to a second bag 3. One possiblesolution is illustrated in FIGS. 20 a, 20 b, 20 c and 20 d. The stack ofempty antislip bags 3 contains the bags 3 in a form in which each bag 3is individually folded in a way in which the bag bottom 4 is madeparallel and adjacent the bag mouth 5 and the skidproofing material 73of the bag 3 is invisible from outside. Thus the bags 3, on top of eachother, only contact the roughened sides 7 of each other, with none ofthe skidproofing materials 73 involved in the inter-bag 3 contacts. Thevacuum head 78 is able to pick up the mouth 5 of the top bag 3 andunfold the bag 3 (with slipping its skidproofing material 73 on itsskidproofing material 73 without difficulty) to complete the bag 3placing operation. Another possible solution is illustrated in FIGS. 21a, 21 b, 21 c, 21 d. The empty bags 3 are prepared in a way in whichtheir bag bottoms 4 are positioned higher than their bag mouths 5. Whenthe vacuum head 78 picks up the mouth 5 of the top bag 3, the top bag 3almost fully separates from the bag 3 one layer below, due to theelevated positioning of the bag bottoms 4. If the vacuum head 78 pulls,horizontally, the bag 3 fast enough, the dynamics can be enough to keepthe bag bottom 4 of the top bag 3 in the air during its horizontaltravel. Another possible solution is illustrated in FIGS. 22 a, 22 b, 22c. The bag bottom 4 of the top bag 3 is picked up by an extra vacuumhead 78 and an extra separating sheet 70 is inserted, pulled in from thedirection of the bag bottom 4, under the top bag 3. The separating sheet70 can be a flexible sheet rolled off from a roll. Then the top bag 3can be used as usual in the background art and the separating sheet 70can retrace before the next cycle. Another possible solution isillustrated in FIG. 23. The layflat bags 3 are prepared in anarrangement in which they, in the stack, have alternating orientationsregarding the direction into which the skidproofing material 73 looks.The 1st, 3rd, 5th, etc bag 3 has the skidproofing material 73 lookingupward while the 2nd, 4th, 6th etc bag 3 has the skidproofing material73 looking downward. Thus the prepared stack of empty bags 3 can beused, with the vacuum head 78, as usual in the background art. Further,FIG. 24 shows a side gusseted bag 3 whose bag mouth 5 is formed in a waythat the upper wall of the lying bag 3 has holes 34 in it adjacently thebag mouth 5, so that some of the vacuum heads 78 are able to directly(temporarily) pick up the lower-lying wall through the holes 34. Thiscan help to avoid problems possibly originating from the bag 3 wallsbeing too soft. Further, FIG. 25. shows a schematic side section of atemporary stack of packages of the mentioned bags 3 filled with blocks11 of plate frozen seafood. Sometimes it is necessary to form atemporary stack of such packages, not needing a stabilisation againstslipping but requiring a possibility of an easy dismantling (for exampleduring a manual restacking of a shipment). The flat block 11 shapedpackages are prepared in an arrangement in which they, in the stack,have alternating orientations regarding the direction into which theskidproofing material 73 looks. The 1st, 3rd, 5th, etc package has theskidproofing material 73 looking upward while the 2nd, 4th, 6th etcpackage has the skidproofing material 73 looking downward. Thus thetemporarily prepared stack of packages can be manually dismantled asusual in the background art. FIG. 26. shows a schematic side section ofa stable stack of packages of the mentioned bags 3 filled with blocks 11of plate frozen seafood. The packages have uniform orientations.

1. A method for forming an antislip flexible material, comprising:providing a flexible carrier having a front surface, the providedcarrier at least partly including a thermoplastic first polymer, thecarrier having at the providing a temperature sufficiently low to keepthe first polymer from melting or softening; providing a hot releasesurface of a first temperature; providing a first layer of discreteparticles including a thermoplastic second polymer, sitting on the hotrelease surface and projecting from the hot release surface tocorresponding terminal ends, in the provided first layer the discreteparticles being at least partly of or above a second temperature, thesecond temperature being above a softening temperature of the secondpolymer, providing in the first layer a tackiness of at least theparticle terminal ends; bringing into an, at least partial, contact, andkeeping in the contact for a contacting time, the front surface of theprovided carrier with the tacky first layer sitting on the hot releasesurface for at least partly sticking the first layer to the frontsurface, and thereafter removing the carrier, and therewith at leastpartly the tacky first layer stuck to its front surface, from therelease surface thereby providing the carrier with a coating of a hotstate, and utilising a heat energy of the hot coating forming a bondbetween the carrier and the coating, thereby providing an antislipcoated flexible material including the carrier and the coating bondedthereto; the removing of the carrier including pulling the carrier outof the contact with a pulling-out force, wherein: providing the firsttemperature above the softening temperature of the second polymer; andproviding the first temperature above any one or both of a meltingtemperature and a softening temperature of the first polymer; selectinga carrier that is spoiled through one or more of breaking, stretching,shrinking, and warping if heated completely to the first temperature andsimultaneously exposed to the pulling-out force; and selecting thecontacting time shorter than a minimum time, which minimum time isdetermined such that the spoiling of the carrier by exertion of heat bythe hot release surface is limited to a predefined allowable extent. 2.The method according to claim 1, wherein the provided flexible carrierbeing suitable for use as a flexible packaging or wrapping material. 3.The method according to claim 1, further including the discreteparticles being in their entireties of or above the second temperatureat the providing of the first layer.
 4. The method according to claim 1,further including providing the second temperature above any one or bothof the melting temperature and the softening temperature of the firstpolymer.
 5. The method according to claim 1, wherein at least portionsof the carrier, the portions including the first polymer, are preventedfrom melting or softening between the bringing into the contact and theforming of the bond.
 6. The method according to claim 1, furtherincluding: the provided carrier at least partly including a heatshrinkable second layer including the thermoplastic first polymer, atthe providing of the carrier the carrier having a temperature below ashrinking temperature of the second layer, providing the firsttemperature above the shrinking temperature of the second layer,providing the carrier in original dimensions thereof, and selecting thecontacting time sufficiently short for preventing the carrier fromcontracting more than 25 percent from at least one of its originaldimensions.
 7. The method according to claim 1, further includingproviding a carrier that loses its stability if heated completely to thefirst temperature.
 8. The method according to claim 1, wherein thecontacting time is selected sufficiently short that the spoiling of thecarrier through any one or more of breaking, stretching, shrinking, andwarping is limited to at most an unessential extent.
 9. The methodaccording to claim 1, wherein the removing includes providing anadhesive force between the front surface and at least a majority of thecontacted tacky particles greater than an adhesive force between therelease surface and the at least a majority of the contacted tackyparticles.
 10. The method according to claim 9, wherein the removingfurther includes providing a cohesive force of the at least a majorityof the contacted tacky particles greater than the adhesive force betweenthe release surface and the at least a majority of the contacted tackyparticles.
 11. The method according to claim 1, further includingkeeping the discrete particles of the provided first layer sitting onthe hot release surface long enough to provide at least some of thediscrete particles in an at least semiliquid state and having firstcontact angles with the release surface.
 12. The method according toclaim 11, wherein at least some of the first contact angles beingsmaller than 90 degrees or smaller than 85 degrees.
 13. The methodaccording to claim 1, wherein an outer surface of the discrete particlesof the provided first layer is made up of a first portion contacting therelease surface and a second portion out of a contact with the releasesurface, an area of the second portion being greater than an area of thefirst portion in at least a majority of the provided discrete particles.14. The method according to claim 1, wherein the provided hot releasesurface is either essentially flat or it at most has a patternindependent from a distribution of the discrete particles of theprovided first layer.
 15. The method according to claim 1, wherein thecontacting time divided by an average surface mass of the carrier isprovided to be at most 0.020 s·m²/g.
 16. The method according to claim1, wherein the discrete particles of the provided first layer sitting onthe hot release surface project from the release surface to respectiveparticle heights, in at least some of the discrete particles theparticle height equalling at least 0.1 times a smallest top-plan-viewextent of the particle.
 17. The method according to claim 1, furtherincluding providing, in the antislip coated flexible material, anaverage surface mass of the coating lower than 1.5 times an averagesurface mass of the carrier.
 18. The method according to claim 1,further including providing the heat energy of the hot coating suitablylow for maintaining, without a need for a chill-roll cooling, a breakingstrength of the carrier sufficient for a rewinding of the carrier. 19.The method according to claim 1, wherein at least some of the discreteparticles in the provided first layer are essentially molecularlyunoriented.
 20. The method according to claim 1, further includingproviding the first layer of the discrete particles sitting on therelease surface with a random distribution.
 21. The method according toclaim 1, further including providing the carrier including a fabric, andpreventing the coating from essentially penetrating the fabric.
 22. Themethod according to claim 1, wherein the coating of the antislip coatedflexible material is formed to be discontinuous, and the coating isformed to include a multiplicity of discrete roughening projectionsprojecting from the front surface of the carrier, each rougheningprojection provided with a foot, the foot being an end of the rougheningprojection bonded to the carrier.
 23. The method according to claim 22,further including providing at least some of the roughening projectionswith a second contact angle of between 90 and 178 degrees or of between92 and 178 degrees with the front surface in at least one side view ofthe roughening projection.
 24. The method according to claim 22, furtherincluding providing at least some of the roughening projections with asubstantially flat top forming an edge at least partially surroundingthe substantially flat top.
 25. The method according to claim 24,further including providing at least a majority of the rougheningprojections with the substantially flat top.
 26. The method according toclaim 24, further including the edge completely surrounding thesubstantially flat top, and the edge essentially forming a circle. 27.The method according to claim 24, further including providing theroughening projection with an edge angle being an angle, measuredthrough the roughening projection, closed between the substantially flattop and a mantle surface extending from the edge to the foot, the edgeangle being smaller than 90 degrees in at least one side view of theroughening projection.
 28. The method according to claim 24, furtherincluding forming at least one side view of the roughening projectionstrictly tapering from the edge to the foot.
 29. The method according toclaim 24, further including tops of at least a majority of theroughening projections essentially being in alignment along a planeparallel with a general plane of the front surface.
 30. The methodaccording to claim 22, wherein during the contacting time a portion ofthe front surface, between neighbouring tacky particles, is kept out ofa contact with the release surface.
 31. The method according to claim22, further including providing two nip rolls and pressing the carriertoward the hot release surface within a nip between the two nip rolls toprovide the contact between the front surface of the carrier and thetacky terminal ends of the particles, exerting on the carrier a nippressure between 0.001 and 80 N/lineal cm or between 0.002 and 70N/lineal cm.
 32. The method according to claim 22, further includingproviding both the first temperature and the second temperature above afusing temperature at which the first polymer and the second polymer arecapable of fusing together.
 33. The method according to claim 22,further including providing the first temperature at least 30° C.degrees higher than both the softening temperature of the second polymerand at least one of the melting temperature and the softeningtemperature of the first polymer.
 34. The method according to claim 22,further including providing the second polymer of a melt mass flow rateof 0.1 to 300 g/10 min determined at 190° C. under a load of 2.16 kg inaccordance with ISO 1133-1.
 35. The method according to claim 22,further including providing the carrier including a fabric woven fromoverlapping warp and weft thermoplastic tapes or yarns, and selectingthe utilised heat energy, of the hot coating including the rougheningprojections, suitably for forming the bond between the carrier and theroughening projections without fusing together the overlapping warp andweft tapes or yarns under at least some of the roughening projections.36. The method according to claim 22, further including providing theantislip coated flexible material capable of a slip-decreasingmechanical interlock in a shearing direction with a skidproofingmaterial, of an ordinary polypropylene spunbonded nonwoven fabric of anaverage surface mass of 17 g/m² and filament thickness of between 25 and30 micrometres, due to the roughening projections having suitablecloseness and geometric features with respect to the skidproofingmaterial for forming mechanical bonds with the filaments of theskidproofing material in the shearing direction.
 37. The methodaccording to claim 22, wherein the forming of the bond between thecarrier and the coating including the roughening projections includesfusing the roughening projections with the carrier utilising the heatenergy of the hot roughening projections.
 38. The method according toclaim 1, further including: providing respective inter-particledistances between neighbouring discrete particles of the provided firstlayer, and providing the hot release surface in a form of a revolvingendless belt having a running direction, and keeping the endless beltalternatingly shifted, perpendicularly to the running direction, betweentwo lateral end positions, providing a lateral displacement of the beltbetween the two end positions, the lateral displacement being equal toor greater than an average of the inter-particle distances.
 39. Themethod according to claim 1, further including forming a packaging bagor packaging wrap that includes the provided antislip coated flexiblematerial, with at least a part of the coating looking toward an outsideof the bag or wrap.